I think we all have our notions of what college will be like and they're all pretty much wrong.
Here's my take:
Go to most of your classes. Not all professors care about attendance, but some do, so you'll want to figure who those are before you start a skipfest. Even if your classes are boring, I'd urge you to attend because it's something to do and it builds structure and schedule into your life. If anything it's something to do with your day and gets you out of the house/dorm. Oh and sometimes, if you attend frequently the professor will give you a break on grades.
Pay attention in class, take notes on shit you don't already know. Read a little before class if the subject matter is something you're not familiar with. Not saying to read books and become an expert, just skim a chapter or two. Answering questions is really up to you, if you like to answer questions do it, if not then just pay attention in case it's important.
Studying: There are several schools of thought. Some say it's best to study all the time regardless of when exams are. But lets be real, thats not going to happen. You usually want to give yourself a 5 day window to study before an exam. 3 days is okay too, it just depends on how fast you retain facts or "learn". So long as you occasionally enter the class room and do a minimum of reading you should already have retained a bit of instruction. Note the word usage of "should have". Because most of the time, you won't. The honest truth is that University will be periods of stagnation and chill time mingling with bouts of studying, panicked paper writing, and presentations you probably won't have prepared for.
Also, get out, meet people, try new things. Uni is work, but it's relatively easy compared with most things in life. Stay as long as you can. And pay attention.