Whompyjawed

When I started photoshop, I used various tutorials from DA "Resource and stock images" category ONLY for the technical aspect of the program, learning the features, processes shortcuts, ect. Only use these for learning the program, there are a lot of unprofessional artists out there, dumping tutorials, and they can mess a newbie up with bad habits. If your instructor is worth anything, s/he will be able to tell you these things and you wont have to bother with tutorials at all.

Use references ALL the time. The faster you get a hang of studying them, the faster you can improve your work. Never reference art, only photos. Reference things around you, draw exactly what you see.

This tutorial sums up anything I can ever really tell you.
[link]

Other than that, practice. Practice for hours. Carry a sketchpad with you. Draw until your hand cramps and then keep drawing. If you have to, turn your internet off to keep your focus. Draw over and over and spend a minimum of 15 minutes on a single piece. Just do it. Art will not come out of you like magic once you have read a bunch of how-to's and tutorials, it's 95% patience and hard work, exercise and developing coordination.