Usability heuristics
Rules of thumb for screens people can use without stopping to think: clear status, plain labels, one obvious next step, a way back.
20 usability heuristics most used in the teardowns first
Clarity
Every word, label and visual on a screen should mean one thing and match what actually happens when the user acts.
Transparency
Show the full price, terms and data use up front, in plain words, so people know exactly what they are agreeing to.
Show, don't tell
Let people see or try the product's result, with examples, previews or demo data, instead of describing features in words.
User control and freedom
Give people a clear way to skip, go back, undo or leave, so no step traps them in a flow they did not choose.
Visibility of system status
Keep users informed about what the system is doing and what their actions caused, through timely, clear feedback.
Visual hierarchy
Use size, contrast, color and position so the most important element on a screen is the one people see and act on first.
Contextual help
Guidance that appears inside the real interface at the moment and place a user needs it, rather than up front.
Progressive disclosure
Show the few options most people need first, and move advanced or rarely used details to a second step.
Discoverability
Make features, options and content easy to come across, with clear cues that say what they are and why they are worth a click.
Signal vs noise
Every extra element, alert or interruption competes with what matters on the screen, so cut anything that doesn't help the current task.
Consistency and standards
Make the same thing look, read and behave the same way everywhere, and follow the conventions people already know from other products.
Recognition over recall
Show options, labels and previous inputs on screen so users can pick what they need instead of remembering it.
Clear call to action
Each screen has one obvious next step, and its button says exactly what will happen when you press it.
Flexibility and efficiency of use
Offer more than one way to get a task done, with shortcuts and fallbacks, so both new and experienced users can move at their pace.
Error prevention
Design screens so mistakes are hard to make: constrain input, check it as people type, and confirm only risky actions.
Cognitive load
Working memory is small, so every extra thing users must read, compare or remember leaves less for the actual decision.
Mental models
Users act on their own beliefs about how a product works; designs that match or clearly teach those beliefs are easier to use.
Expectation setting
Tell people before they start what a step will ask of them, how long it will take, and what will happen afterward.
Preserve context
Carry the user's choices, location and purpose through each step so they never have to re-enter, re-choose or reorient.
Affordance
An element's look should signal what you can do with it: buttons look pressable, carousels look swipeable, text looks like text.