"Make sure you really understand the foundational concepts covered in the first few weeks (vectors, vector functions, parametric, etc.). The second half of the course builds heavily on those concepts. You don't need background on those topics beforehand, just stay on top of class material as it's being covered.
At least for Sethian's class, you don't need to be too worried about the crazy integrals from 1B/calc BC. Just know a couple trig identities, you'll be set. Also don't worry about sequences & series - they're not dealt with at all in 53. If you have AP credits and can skip out of 1A/1B, I would recommend doing so. Berkeley 1A/1B are hard for the sake of being hard. If you feel shaky, go on KhanAcademy and do some practice problems there.
When looking for GSIs to do discussion with, do not pick Nima Moini. I had him and switched to another GSI. He took like 3 discussion sections to cover one thing that wasn't important anyway, and he explained it in a confusing way and then got impatient when the whole discussion section didn't understand. I switched into Boyan Xu's section - he's great, explains things well and clarifies concepts. Not sure if he's GSI-ing again for 53 though.
If you need to do a last minute discussion section switch and are having trouble wrestling with CalCentral, you can talk to this lady named Jennifer Sixt, located on 9th floor Evans, and she can help you override CalCentral. "
-Ashley, Team Sapphire
"Very difficult class, however, very interesting and applicable to higher level physics concepts. "
-Natalie, Team Diamond
"A class that is a reasonable advancement from 1B or calc BC. Interesting and easy if you understand calc well, harder if not."
-Andy, Team Emerald
"You need to go to office hours, and ask questions, especially on the 2/3 of the class "
-Alex, Team Ruby
"First two midterms were fair. Final was hard, but as usual, they curve it so in the end it was ok. "
-Edgar, Team Sapphire
"Study a lot "
-Lizzette, Team Emerald
"This class was fairly interesting. Relaxed for the first portion but became very much challenging near the end when you have to understand conceptually what the many theorems represent. This class definitely does not use extensive Math 1A and 1B concepts. Difficulty of integrals was very much reduced. The only hard concept covered here that you should have seen from the previous courses was limit delta epsilon tests but that is probably not going to be on an exam for various reasons. " - Alvaro, Team Sapphire
"53 takes 3D space and vectors heavily into consideration so it really tests your knowledge of 1B material. Definitely an Interesting class that starts relatively easy and gradually increases in theory. " - Daniel, Team Ruby