I would also like to add, that I am currently in school for Graphic Design and agree with dillingerxcape that it is hard to explain online, but a few suggestions I have are:
-Definitely play around! I am constantly learning new things in there.
-I would suggest that if working on a file, duplicate the bottom layer (unless it is a blank background). In addition to making adjustments in further layers, this allows you to quickly see the difference in where you started and where you are now. As well as keeps a non edited version available.
-One thing that I have done, after learning some basics, is to start memorizing the keyboard shortcuts for my most used tools, it just keeps things moving fast.
-This one is similar to the duplication one above, but I must say layers layers layers. The ability to do something and go back and turn it off if you don't like it is gold.
For tutorials, I would suggest
Photoshop Tutorials - PSDTUTS They have really cool tutorials, in my opinion. They explain them well too!
I hope this helps, and as Bert Monroy says (from the Pixel Perfect show that someone posted) "remember always play, the best way to learn is to play". (at the end of his pixel perfect episodes)
