The Short and Sweet

Optimised design is:
 
1. Useful – it does the job.
2. Efficient – it is the fastest and simplest to do the job.
3. Clear – it is easy to understand how to achieve the job.

NOTE: These optimisation factors are deeply interrelated.

Useful

Design to achieve stories

Mission First

Design for users

Achieve the mission

Start well

Be Flexibly Logical

Present information logically

Be flexible

Be helpful

Be Navigable

Always keep the user informed

Always provide search

Always provide escape

Efficient

User interactions to achieve story

Minimise User Actions

Do not force unnecessary actions

Make it simple not simplistic

Minimise repeat efforts

Optimise Compositon

Optimise the use of real estate

Make it simple not simplistic

Minimise repeat efforts

Minimise Repeat Effort

Show, don’t hide

Remember and default

Expand is your friend

Clear

Visual arrangement

Layout Drives Clear Communication

Communicate Clearly

Organise the composition

Don’t clutter but do fill

Use visual cues

Be Consistent

Be consistent with placement and styles

Implement consistent workflows

Be consistent with brand voice

Be Accessible

Font and control size

Use colour wisely

Don’t forget sound and touch feedback