Most important rules for design

in order of priority (exept the last). I wrote these sometime in October 2001. I still think they are a good checklist. However, if you understand the meaning of the points, you may not need it.

1. Learn who the users are, what they are doing, when and where they are doing it, how fast and how often.
2. Test what you have made, or better make cheap protypes and test while you have time to make them better.
3. Document what you are doing, otherwise it is lost.
4. Make the possible choices visible for the user, so she can see what she can do.
5. Make the design consistent: And decide how it shall be internally consistent and what other designs it shall be consistent with.
6. Make the density of information as high as possible: Do not waste space.
7. Reduce the distance, for instance the number of screens, between different functions and different types of information.
8. Put as few restrictions on the user's actions as possible.
9. Reduce the number of physical actions the user has to do.
10. Put things which are closely related close together and space between things which are not closely related.
11. Separate different types of information through careful use of different colors, brightness, slopes or textures.
12. If the user only likes the design, it is not good enough. If she smiles when using it, it is good.