Common Mobile UX Mistakes and How to Avoid Them

The six mistakes you see most often

1. Touch targets that are too small.
2. Main navigation hidden behind a hamburger menu.
3. Mandatory sign-up before the user sees any value.
4. Errors that don't explain what happened or what to do.
5. Key actions out of thumb reach.
6. Forms that ignore the keyboard.

Below, for each one: what the problem looks like and how to fix it.

1. Tiny touch targets

Before: a 20×20 "close" icon in the corner, text links packed tightly together. Users miss and hit the neighboring element.

After:

• Minimum touch target is 44×44 pt in Apple's Human Interface Guidelines and 48×48 dp in Material Design.
• The icon can stay visually small — enlarge the tappable area around it.
• Leave spacing between adjacent buttons, especially when one is destructive ("Delete").

2. Hidden navigation

Before: every section lives in a side drawer behind a three-line icon. People don't know what else the app offers and stick to one screen.

After:

• Use a tab bar (bottom navigation) for the 3–5 main sections: always visible, one tap away.
• Keep the drawer for secondary items: settings, help, legal pages.
• Label icons with text — an icon alone is often ambiguous.

3. Forced sign-up at the door

Before: the first screen is a form with email, password and confirmation. The user doesn't yet know why they need the app and closes it.

After:

• Let people explore without an account: catalog, demo data, guest mode.
• Ask for sign-up at the moment of value: saving a result, placing an order, syncing.
• Offer fast options: Sign in with Apple, Google, phone number.
• Mind the App Store rules: if the app lets users create an account, it must also let them delete it.

4. Unclear errors

Before: "Error 500" or "Something went wrong", and the entered data is gone.

After:

• Explain what happened and what to do: "No internet connection. Check your network and tap Retry."
• Validate inline, next to the field, not as a list after submission.
• Keep the user's input when an error occurs.
• Distinguish user problems (wrong format) from system ones (server failure) — in the second case, don't make the user fix anything.

5. Ignoring the thumb zone

Before: the main "Checkout" button sits in the top-right corner of a large screen, so users need their other hand.

After:

• Put the screen's primary action at the bottom, within easy reach: a sticky button, tab bar, bottom sheets.
• Rare and destructive actions can live further from the thumb.
• Test layouts one-handed on a real phone, not just on a monitor.

6. The keyboard vs the form

Before: a phone field opens a letter keyboard, and the keyboard covers the input and the "Next" button.

After:

• Set the input type: phone, email, number — the system shows the right keyboard.
• Enable autofill so the system can fill in phone numbers, addresses and SMS codes.
• Configure the keyboard action: "Next" moves to the next field, "Done" submits.
• Scroll so the active field and submit button are never hidden by the keyboard.

A Flutter example:

TextField(
  keyboardType: TextInputType.phone,
  textInputAction: TextInputAction.next,
  autofillHints: const [AutofillHints.telephoneNumber],
)

A quick self-check

• Walk through the key flow one-handed on the largest and smallest phones you target.
• Turn off the internet and see what the user gets.
• Hand the app to someone who has never seen it and silently watch the first few minutes.
• Check against the official guidelines: Human Interface Guidelines for iOS and Material Design for Android.