looks like you're just starting out, so here are some helpful tips that I hope will steer you in a good direction.
1. Go to every life drawing workshop that school offers, it is an essential practice and extremely helpful, more so than most of your teachers will be.
2. Study anatomy like crazy, if your going to an AI you probly have the Simblet book, as well as the Albinus Book. GO through them like crazy, draw everything you see in it and make sure you learn both form and function of the muscles.
3. For modeling, when you just start modeling, don't go right into doing concept pieces or anything that you don't have in front of you. A great excercise to do is model the simple items you have at your disposal things that you can turn inyour hand, get close to and examine their detail. It will get you familiar with the program as well as focus you eye on matching reality, as you can see first hand how your model differs from its reference. Another excercise you might wanna try is to model an item, then do it again the next day, increase you speed in modeling it and your level of detail, find new ways to model it and explore your options on going about it, this will make you more versitile and will help you out on future models.
4. Make friends with the people there that are better than you, you'll find you learn a lot more and faster from them than you will from your teachers
5. learn multiple programs, maya, 3ds max, and xsi. Model an object in one, then learn how to do it in the others, your ability to learn new programs fast is a valuable one, and being versitile is key in this industry.
6. Don't rely on your school to make you a good artist, I went to an AI and it like many other like it are there as a business, their intent is to make money and not to make you a great artist, thats up to you. don't limit yourself to the things they teach you, branch out as much as you can, this forums a good start.
I'd rather be rich than stupid