<p>well, I for one didn't really use anything
it just came with time I guess
but I had friends do prep courses just focusing on the math or just buying the real 10 SAT books- Iguess they're the most realistc</p>
<p>Honestly if your 690 then you probably know everything, you just made stupid mistakes. I improved by writing everything down as I went, it feels dumb, but it makes sure that you don't miss anything. Usually I would finish right on time, but if you have extra, go through the last problems (hardest ones) without looking at your previous work and see if you get the same answer.</p>