Focus on the 20% of features used 80% of the time.

Time to make a decision increases with the number of choices.

Target acquisition time is a function of target distance and size.

The simplest solution is usually the correct one.

Users base actions on their preconceived ideas of how a system works.

Visual properties that hint at how an object is used (e.g., a handle).

Similar tasks should have similar interfaces to reduce learning time.

Information is presented only when needed to avoid overwhelming the user.

Verifying an action to prevent unintended errors (e.g., “Are you sure?”).

The system must inform the user of the result of their action immediately.

Minimize memory load by making objects and actions visible.

Users perceive attractive designs as being more functional.

Elements are perceived as either figures (focus) or ground (background).

Things that are close together are perceived as being related.

Elements with similar visual traits are seen as part of a group.

The brain fills in gaps to create a complete image.

Objects moving in the same direction are perceived as a group.

Distinctive items are easier to remember (e.g., a red apple in a green bowl).

Users remember the first and last items in a list better than the middle.

Maximize relevant information; minimize irrelevant clutter.

Colors carry different psychological meanings across cultures.

The ease with which glyphs can be distinguished in a typeface.

Dividing an image into 9 parts to create dynamic balance.

The mathematical ratio of $1.618$ found in nature and art.

Using scale and color to show the order of importance.

Lining up elements to create visual connections and flow.

Mirroring elements creates a sense of formality and stability.

Using differences (light/dark, big/small) to make elements pop.

Using “breathing room” to focus attention and group items.

Breaking a system into smaller, manageable, repeatable parts.

Ensuring a design still works even when certain features fail.

Designing for all users, including those with disabilities.

Avoid unnecessary assumptions; the simplest path is usually best.

People remember uncompleted tasks better than completed ones.

Assuming a system that works at one scale will work at another.

Providing backup methods to prevent system failure.

Experiences are judged by how they felt at their peak and end.

Designing objects to resemble human forms to increase likability.

Visual patterns or phrases that help users remember info.

Limiting actions to prevent user error (e.g., grayed out buttons).