Take advantage of any extra resources you can find - even if that means visiting your instructors after class everyday - sitting in their office - letting them know you are serious and want to succeed.  Figure out how you study and/or learn the best and stick to that.  If you do better studying alone, don't get into a study group.  There are sites online that help you determine your learning style and sometimes the nursing programs even have those kinds of tests available for you (mine did).  Let people know you are going to school and explain that you may not be able to do the things you used to for a while - nights out, social stuff, etc.  But don't deny yourself some time to chill out and relax either - believe me you'll NEED it.  About once or twice a month a few of us from my LPN program would drive to another city and go have a good dinner, drinks and just blow off steam.  It was a lot of fun and helped us recharge.  Clinicals are the times you "learn to be a nurse" so to speak.  All the theory you get in class is a good foundation but clinical is where you learn to apply what you learn in class or read in a book.  Take advantage of every opportunity to perform a new skill or observe something you've not seen before - it will pay off in the end.

Good luck in school!!

I have never been involved in a study group so don't worry about it.  I'm back in school now going for my RN and avoid them like the plague.  I don't feel like they're very useful and have found that a lot of times things don't really get accomplished or time is wasted.  There may be instances when you have to work in a group and there will always be at least one who will do as little as possible (just one of the down sides of working within a group).  It's been 12 years since I've been in school and I too am more of the loner type - I just know that I do better on my own when it comes to studying and learing material.  The biggest challenge you may face is "re-learning" HOW you learn. 

I wish you all the best in school.  It will go by quickly.