If you're looking for letters of recommendation, you should be looking at people who can give you good character references (not just academic) and people who can actually attest to you being a certain way.
For e.g. I wouldn't just ask my typical high school teacher for a reference. If you volunteer for instance, maybe ask the Exec. Director. Someone who holds some clout. Remember, alot of your competition (because that's what it is) are looking at getting the best references possible and it's not just their coach (unless the coach used to go to that school).
For the SATs, it's not different than studying for for your LSATs etc. I"d suggest just going to Chapters/Indigo and picking up one of those testing guides and go from there.