Photoshop tips/shortcuts for beginners

Here are my top photoshop tips for beginners like myself … I use photoshop 7/CS & these tips have been quite helpful.. I hope they are helpful to you too. Please, feel free to add yours..

Ctrt+N -opens up a new document [did i need to write that?]

Ctrl+Tab -Switch between documents within photoshop

Ctrl+F4 -Close current document