Don't fuck up!
Seriously though, just do what they suggest you do, and don't stress out. It always cracks me up when people stress so hard about exams, but if you have already done the work you don't need to stress. That doesn't mean you still won't have to work hard, but that doesn't mean stress.
Next always get your work done early. As soon as you leave class start your work, go to the library w/e just get it done. At night there are a million distractions and if you want to enjoy your time (which you will) do it by getting your work done first.
The other big thing, go to class!
-One more thing, get a degree that is worthwhile. Are you undecided now? If so take very heavy math classes it will pay off seriously in the future. Get a plan and follow through with it. It may seem like a lot of work but in reality it is not. A shitty job for the rest of your life is a lot harder life, than if you got a great education and having a good job the rest of your life.