I'll start with this, somewhat paraphrasing my old professor here:
Draw for fun, Draw from life, Draw a lot.
I think drawing is something that one should enjoy, since you are probably going to do it a lot in this business. And practicing is essential, if you have fun while doing it, you are much more likely to be motivated to do it.
drawing from life is a very important part of the classical practice. It trains your eyes and tunes your observational skills. But this is not just for replicating the realities, both observational practice and drawing from imagination require you to understand how light interact with forms. While the basic concept can be taught, nothing really beats drawing from life when it comes to training you to understand shades.
Obviously, you should draw a lot , with correct practice and some research, you can improve your abilities tremendously, but there is not short cuts, practice practice practice. :3
Another advice, you should mix your lecture class and studio classes. Do not wait to do studio classes. In two semester I decided that I should take on 4 studio classes (each, Life drawings, painting, ceremics, studio photography, and 300 level drawings), I thought it would be fun, oh boy, how wrong I was. It was the most hellish and expensive two semester I have ever experienced. So don't take your lecture or studio classes all at once. >.> Pace them and mix a bit its probably a good thing.
My specialization is drawing, although a lot of guys in the department seen to want me to switching to painting while I was at school. <.<;