The best designers employ specific habits, learned practices, and observed principles when they work. Here are a few of them.

1. Experts involve the user
2. Experts design elegant abstractions
3. Experts focus on the essence
4. Experts simulate continually
5. Experts look around
6. Experts reshape the problem space
7. Experts see error as opportunity
8. Experts think about what they are not designing

(read the article: nice pictures to visualize the different concepts :-))