I was in the same position as some of you. I came to CAL as a transfer student so my fall semester was a bit crazy. I was taking upper division classes like biochemistry (which was quite an adventure). Nonetheless, my first semester was a learning experience.
First, don't overload yourself with a workload that you can't handle. Start out small and figure out exactly how much you can handle. Not everyone is the same. Some can handle 6 hours or less of sleep per night, a part-time job, 17 units, and be an active member of more than one club. On the other hand, if you're like me, you can only handle little more than half this load. Second, it's really important to balance everything. Academia is important. I mean, we're here to learn aren't we? However, it's also important to get involved with the campus. There are MANY opportunities at CAL that you should utilize. I regret not getting involved with things like research, clubs, etc. I was definitely missing out. Third, enjoy your experience at CAL. There were times when I wondered how I ever got into CAL and it got in the way of enjoying the Berkeley environment. I know for some people, stressing over grades and classes can have the same affect. Try to make the best out of your four years (or even more) at Berkeley. Think about it. You're at CAL, the top public university in the nation! Have fun!