Ok, if you like to paint using adobe photoshop + tablet combination, here are the shortcuts to be know:
Hold R + moves pen while clicking = rotate the canvas, pretty useful if you can easily do some movements in one way, but have trouble doing in some other direction.
type H = pan the canvas so you can paint a different area
type B = select the brush tool, which pretty much is the same as get back to drawing mode
Ctrl + Alt + Z = goes back a history item
Ctrl + Shif + Z = goes forward in history
Ctrl + A = selects all (type Del to delete everything in a layer)
Ctrl + D = de-selects all
Also, to increase productivity, I draw with as many layers as possible - usually two big groups, one where I store lines per objects in drawing, and the other to store the colors for it. ALWAYS NAME THE LAYERS, this will help you a lot in a big drawing.
Keep system updated: install your tablet drivers - if you don't, your computer probably will understand it's pressure, but will interpret the position as relative instead of absolute (like a touchpad).
And if you only plugs your tablet to do drawing and then unplugs it for some reason, remember to plug the tablet in your computer BEFORE clicking to open adobe photoshop, or else photoshop won't load your defaults, meaning, pressure won't work the same way you had configured it.
Per last, you can map any sensors on your pen to size, color, opacity: click Window, Brushes and select color dynamics, shape dynamics and other dynamics, and set it's properties to suit your needs - do experiment having some jitter if you would like to add some more randomness to your drawing.
If you use some more stuff, please tell me. Also I'm looking for a good alternative to using zoom in alt + scrollwheel, since I don't like to have to put down the pen only to change my zoom settings.