any basic things i should know about?

for us history the best thing you can do is READ, READ and READ. Really, the more you read, the higher you'll score. Don't spend all your time memorizing every little detail though, focus on things that are important(usually bolded in some prep books)
for math, I would say buy the barron's book, read the lessons and do your practice problems.

For US History, don't try to memorize, but rather understand. Don't memorize all the dates and all the names, but know the general outline of a certain event, why this happened. Kind of like if you were telling a dream you had. You may not remember every single second of it, but you can still convey the important message in it. Also, practice your essay skills. One thing my AP US his teacher taught me was at the end of the essay, try to write something that shows you have knowledge outside of the question being asked. So for example, let's say the essay prompt asked about the Revolutionary War and its significance. Write 90% of your essay about the prompt, addressing the question, analyzing the situation, but for the last paragraph or two, add a couple of sentences about say...what would happen if the war never occurred, or how the Britains could have done better, etc etc. Or you can even write an extra paragraph to argue AGAINST your point. So let's say the essay prompt asked you about proclamation of emancipation. You can spend most of your essay writing about how it helped slavery, how it helped the war, blah blah blah. But towards the end, you can say something like how the proc of eman didn't have much executive power. In a way, *subtly*, and I mean subtle, argue against your point by point out something that tells the reader that you know more than just spitting out information from the history book. I was pretty lazy in my AP history class, and figured that it was too much info to memorize for one test, but I ended up getting a good score on all my essays despite the fact that I BSed on half of them. I think that technique helped that 5 I got

for sat ii math 2, you absolutely have to watch the time and pace yourself accordingly. don't panic if you don't finish all of the problems cuz i didn't do 6 of them and i still got a 780. just practice a lot. i remember i did a practice test every single day the week of. good luck