How to: Improve your designing skills

I have found an interesting post from PSDtuts. They are all about improving your designing skills (e.g. tips for Photoshop, Illustrator, After Effects, or other (free) software)
Today I will show you a few of these links, to get you started.

PSDtuts: 10 Step to Improve Your Photoshop Skills
GMZ DesignMaster rules:
Rule 1: Fonts
Rule 2: Colours
Rule 3: Contrast
Rule 4: Spacing
Rule 5: Depth
GMZ: What makes a great logo
SmashingMagazine's tips