If you aren't very confident in your english skills, try photoreading the dictionary and grammar books (for the writing section) frequently. The SATs are given a month apart here in the U.S., i'm not sure how it works in Korea, but keep up photoreading your SAT prep materials in between. If you are having trouble with vocab, you can also try the princeton review vocab prep books. they have ones with cartoons and everything to help you remember.
On the actual SAT test, i didn't photoread the critical reading section. i read them through in the 'flow' state, and i found that i remembered more details and didn't have to go back to search for the answers as much. i always had leftover time at the end to go back and check my answers. This method also worked really well on SAT2 literature exam.
don't worry--i'm sure you'll do fine! once junior year is over you'll look back and see that its not so bad. i just hope photoreading will help get me out of senioritis. 
