Good mobile UI comes from understanding users, not mastering design tools. The principles that make apps intuitive—thumb-friendly tap targets, clear visual hierarchy, predictable navigation—aren't secrets reserved for trained designers. They're documented patterns that anyone can learn and apply.
This matters now more than ever because AI handles the execution. Tools like Anything translate plain-English descriptions into professional interfaces, which means the barrier has shifted. The question isn't "can you design?" It's "do you know what to ask for?"
Most apps fail on design before users even try the core functionality. A login screen with cramped buttons, a feed with inconsistent spacing, a checkout flow that feels off—these small friction points signal "amateur" and erode trust. Users decide whether your app is worth their time in the first few seconds, and that judgment is almost entirely visual.
This guide covers the principles behind mobile UI that converts, the patterns professional designers use repeatedly, and real examples showing what production-ready design looks like. By the end, you'll recognize why certain apps feel polished, and others feel broken—and you'll know exactly what to describe when building your own.
Why mobile UI design matters more than you think
Users judge app quality in milliseconds. Before they read the headline, tap a button, or understand the value proposition, they've already formed an opinion based purely on how the app looks. Design is the first test of credibility—and most apps fail it.
Poor UI doesn't just frustrate users. It kills conversion before they reach your core value. A potential customer who lands on a cluttered dashboard or struggles with a cramped login form doesn't think "this app has usability issues." They think "this app isn't trustworthy" and leave. The functionality behind that screen never gets a chance.
The difference between "looks like a real app" and "looks like a weekend project" determines whether users pay. Apps succeed partly because they work—but also because they look like they work. Design credibility converts to revenue.
That's why apps that "don't look AI-generated" earn trust that translates directly to money. When your app feels professional, users assume the underlying functionality is professional too. They're more willing to enter payment information, more likely to recommend it to others, and more forgiving of minor issues. Design isn't decoration. It's the foundation of user trust.
Core principles of mobile UI design
These five principles form the foundation of every well-designed mobile app. They're not trends or personal preferences—they're patterns that work because they align with how humans naturally interact with phones.
Thumb-zone design
Mobile is one-handed by default. People hold their phones while walking, eating, or lying on the couch. Design for how users actually hold devices, not how they sit at desks.
- Primary actions belong in the bottom third of the screen. That's the natural thumb zone—the area users can reach without adjusting their grip. Navigation bars belong at the bottom, not the top.
- Place elements by reach difficulty. Bottom center is easy, sides and middle are moderate, top corners are hard. Put your most important buttons where thumbs naturally rest; reserve top corners for settings and overflow menus.
- Specify placement when describing your app. "Put the main action button at the bottom center. Move navigation to a bottom tab bar. Keep the settings icon in the top right corner."
Visual hierarchy
Users scan, they don't read. Your design needs to guide their attention deliberately, showing them what matters most before they consciously decide where to look.
- Every screen should have one primary action. Use size, color, contrast, and spacing to make it visually dominant. Secondary actions should recede. If everything looks equally important, nothing feels important.
- Show what matters now; hide complexity until users need it. This is progressive disclosure—a settings screen doesn't need every option visible at once, and an onboarding flow doesn't need to explain every feature upfront.
Consistency and predictability
The same action should look and behave the same everywhere in your app. Users build mental models quickly—consistency reinforces them, inconsistency breaks them.
- Follow platform conventions. iOS users expect swipe-from-edge to go back; Android users expect a back button. iOS places primary actions on the right; Android uses floating action buttons in the bottom right. When your app follows these conventions, it feels native.
- Maintain visual consistency throughout. Same spacing, same typography, same color usage across every screen. When elements align properly and colors follow a clear system, users perceive quality even if they can't articulate why.
- Make navigation predictable. Users shouldn't think about how to move around—that mental energy should go toward their goals. If they can guess where a feature lives before looking for it, you've designed good navigation.
Feedback and responsiveness
Every tap needs acknowledgment. When users interact with your app, they need to know the app heard them—otherwise they wonder if they tapped hard enough, if the app froze, or if they should try again.
- Provide immediate visual response to all interactions. Buttons should change when pressed. Form submissions should show loading states. Completed actions should display confirmations.
- Make error states clear, specific, and actionable. "Something went wrong" tells users nothing. "Your password must include a number" tells them exactly what to fix. Place error messages near the problem, not at the top of the screen.
- Use micro-interactions to make the app feel alive. A toggle that slides smoothly, a card that bounces slightly when selected, a heart icon that pulses when tapped. These small touches add personality without slowing users down.
Accessibility as foundation
Accessible design isn't an afterthought—it's better design for everyone. Larger touch targets help users with motor difficulties, but they also help everyone using the app one-handed on a bumpy train.
- Touch targets should be at least 44 by 44 points on iOS or 48 by 48 dp on Android. Make buttons that don't require precision tapping. Small targets frustrate everyone.
- Maintain sufficient color contrast. At least 4.5 to 1 for body text, higher for smaller text. Low contrast might look sophisticated in mockups, but it fails anyone with vision impairment.
- Don't rely on color alone to convey meaning. If an error state only shows red text without an icon, colorblind users miss it. Pair color with icons, text, or other visual indicators.
Essential mobile UI patterns
Patterns are proven solutions to common design problems. When you know the vocabulary, you can request exactly what you need: "Add a bottom navigation bar with 4 tabs" instead of "make it easier to move around." These patterns exist because they work—millions of users have already learned them.
Navigation patterns
How users move through your app. Good navigation feels invisible—users get where they want without thinking about how.
- Bottom navigation bar: The standard for apps with 3 to 5 top-level destinations. Icons and labels sit at the bottom, always visible and within thumb reach.
- Tab bar: For switching between views within a section—like "All," "Unread," and "Groups" in an inbox. Typically sits at the top of the content area, below the header.
- Hamburger menu: The three-line icon that reveals a hidden drawer. Use sparingly—it hides options behind an extra tap. Reserve for secondary items like settings and help.
- Gesture navigation: Swipe to go back, pull to refresh, swipe to delete. Only works when following platform standards—iOS expects edge swipes, Android expects a back button. Don't invent custom gestures.
Content patterns
How information is displayed. Match the pattern to how users need to consume the content.
- Cards: Contained units of related content—scannable, tappable, swipeable. Each card groups information that belongs together. The building blocks of most modern interfaces.
- Lists: Vertical scrolling with consistent row structure. Efficient for scanning large amounts of similar data when users need to quickly find and select items.
- Feeds: Infinite scroll with clear content boundaries. Best for social, news, and discovery interfaces. Requires obvious separation between items and smooth loading.
- Grids: Visual browsing that emphasizes thumbnails over text. Ideal for photos, products, or portfolios. Fits more items on screen but provides less detail per item.
Input patterns
How users enter information. Mobile input is slow and error-prone—every pattern here aims to reduce friction.
- Forms: Single-column with generous touch targets. Multi-step forms showing one question at a time often outperform long scrolling forms.
- Search: Place prominently at the top. Show recent searches and auto-suggestions to reduce typing.
- Selection controls: Toggles for on/off, radio buttons for single-select, checkboxes for multi-select. Using the right control tells users how to interact.
- Date and time pickers: Use native pickers whenever possible. Users know their platform's picker, and native versions handle accessibility and localization automatically.
Feedback patterns
How the app communicates status. Users need to know their actions registered and what's happening next.
- Toast notifications: Brief, non-blocking messages that confirm actions and fade away. "Message sent" or "Item added to cart." No user response required.
- Modal dialogs: Full interruptions requiring response. Use only for critical decisions—deleting data, confirming purchases. If you're showing modals frequently, rethink your design.
- Empty states: What users see when there's no content yet. Good empty states provide guidance and a clear action: "No messages yet—start a conversation."
- Loading states: Skeleton screens beat spinners. Show the shape of content that's loading rather than a spinning wheel—users perceive it as faster.
Onboarding patterns
How users learn your app. Respect their time—get them to value fast.
- Progressive onboarding: Teach features in context, not upfront. Let users start immediately and explain features as they encounter them.
- Permission priming: Explain why before asking for camera, location, or notifications. "We use your location to find nearby stores" gets accepted; a generic popup gets declined.
- Social proof: Show activity from other users. "Join 50,000 people tracking their habits" reduces the perceived risk of trying something new.
- Quick wins: Get users to core value immediately. Let them complete one meaningful action in 30 seconds—long setup flows lose users.
Designing for conversion
Design quality directly impacts whether users trust your app enough to pay. The principles covered so far create apps that feel professional—this section focuses on the specific patterns that turn browsers into customers.
Place calls-to-action at decision points
When users finish reading your value proposition, the button to try or buy should be right there. When they complete a free trial feature, the upgrade prompt should appear naturally. Don't make users hunt for the next step.
Put trust signals where decisions happen
Users look for reasons to feel safe when they're about to spend money—give them those reasons exactly when they need them:
- Security badges near payment fields
- Money-back guarantees near the Buy button
- Review counts near pricing
Design pricing screens with intent
Pricing is where users decide if your app is worth their money. Make that decision easy by guiding them visually:
- Use visual hierarchy to guide users toward your preferred option—usually the middle tier
- Highlight what's included, not just the price
- If you offer a free tier, make the limitations clear so users understand what they're upgrading to, not just what they're upgrading from
Simplify checkout ruthlessly
Every extra step loses users. Every unnecessary form field loses users. The path from "I want this" to "I bought this" should be as short as possible:
- Reduce checkout screens (4 to 2 if possible)
- Remember payment methods for one-tap purchase
- Eliminate optional fields entirely
Prompt Engineering
The shift in who can create professional apps is real. Design knowledge used to require design tools—Figma, Sketch, years of practice. Now it requires clear descriptions. The tools that translate language into interfaces have reached the point where knowing what you want matters more than knowing how to build it pixel by pixel.
That's where this guide comes in. The principles and patterns covered here give you the vocabulary to describe exactly what you need.
What to include in your prompts
The more specific your description, the more accurate the result. Cover these four elements:
- Layout structure: What goes where on screen
- Visual hierarchy: What should stand out
- Interaction patterns: What happens when users tap
- Platform conventions: iOS vs Android expectations
Vague prompts vs. specific prompts
Compare these two approaches:
- Vague: "Make a nice login screen."
- Specific: "Create a login screen with the app logo centered at the top, email and password fields with labels above them, a large blue Login button below the fields, and a 'Forgot password?' link underneath. Add 'Sign in with Google' as a secondary option at the bottom."
The second prompt produces predictable, professional results because it specifies layout, hierarchy, and interaction elements. You're not asking the AI to make design decisions—you're telling it exactly what you want based on the patterns that work.
The skill that remains
The remaining skill isn't technical—it's knowing what good looks like and being able to articulate it. When you understand thumb zones, visual hierarchy, and platform conventions, you can describe exactly what you need.
Anything's custom design model is trained specifically to produce apps that don't look AI-generated. When you describe the principles from this guide—"bottom navigation with 4 tabs," "cards with 16 points of padding," "primary action button in the thumb zone"—the platform executes at a professional level. Mobile and web apps from the same project. App Store submission included. The technical barriers that used to require months of development work are handled automatically.
From principles to production: building professional UI without design skills
You now have what most people lack: the vocabulary to describe professional mobile UI. You can name the patterns, specify the structure, and articulate what good looks like.
That knowledge used to be the starting point. You'd still need to learn Figma, hire a designer, or spend months translating your vision into pixels. Now it's the finish line. Describe what you want, and AI builds it.
Anything takes this further than other tools. The platform's custom design model produces apps that don't look AI-generated—professional interfaces that earn the trust users need before they'll pay. Stripe payments, Google login, App Store submission—the infrastructure that used to block non-technical builders is already built in.
A finance professional used Anything to build AI tools that earned $34,000. A medical student launched a CPR training app charging $85 per month. They didn't learn to code. They learned to describe what they wanted—the same skill you've been building throughout this guide.
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