If you're thinking about taking the math or science tests, make sure you have a really good working knowledge in the subject because there really specific. the english test is probably the easiest, just because everyone knows English to some extent.

You need at least two years in a language to do well on the language subject tests, and if you're going to do a listening one then make sure you have an advanced knowledge of the language.

i think the key with SAT IIs is to take the tests that you would do best on. Take test in subject areas where you would accel. Like for me, it's math. I took the math level one test first and did pretty well (750) so then I took the level 2 test. I didn't do quite as well, but that's because the test is harder.

I took the spanish test and did kind of badly. I only got a 560. But on the Latin test i got a 770

http://www.collegeboard.com/student/testing/sat/about/SATII.html

There's a link to the list of all the SAT subject tests (they got rid of the name "SAT II")