Dmitry Fadeyev wrote a great article for Smashing Magazine called 10 Useful Techniques To Improve Your User Interface Design. This article is a must read for anyone involved in creating Web or intranet products and many of the techniques have direct or analogous application for desktop and mobile interfaces.

If you don’t have time for all 10 (shame on you), the 3 most important are #1 Padded block links, #7 - Auto-focus on input, and #10 - Verbs in labels.