You never really keep up; you just roll with it. Time management is key.
This. Pretty much sums up my quarter system life so far.
Here's some of my personal tips:
1) Make a study strategy for yourself that you know works for pretty much every class. It'll help when you're swamped and need to focus.
2) Take breaks and have fun! It's important to keep yourself from burning out by letting loose with your friends. Personally, going to special interest clubs and organizing events as an officers is socially fulfilling and hits the leadership "check box," if your thought process is so inclined.
3) Take a heavy course load when you start. Yes, people will tell you to take it slow when you start, just so you can adapt to college life. I think if you force yourself to keep up when you first start, you're all that much more prepared for your upper division coursework and every other thing you want to fit into your hectic schedule. And if you need to lighten your courseload, you don't have to worry about graduating later.
Know the kind of person you are, this is no reason to start college off on the wrong foot. If you know 100% you aren't this kind of person, don't do it.
4) I make small goals to accomplish everyday so that I am not totally overwhelmed by all the due dates. Of course, I still procrastinate on somethings and you have to learn to be okay with that. Nobody is ever on schedule all the time. Be flexible with yourself. If you have a paper due in a week and your friends want to go out somewhere special,
GO OUT! The paper can wait a day, and I am always more productive after a great night.
These are mostly general study/college tips, but
#3 has definitely helped me the most. I am prepared to tackle all my more challenging upper division courses and take fewer classes to spend time on other ECs.