How to prepare for the PSAT

As a sophomore I took the PSAT and got a 1260 which was rather disappointing. I got a 670 in the Reading and only a 590 in the math section. The reason I scored so low on the math section was because I took algebra 1, geometry, and algebra 2 in all before my freshman year. I have basically forgotten most of everything before Algebra 2 and that is fairly rusty too. So how should I study the math section? Also what should I do to study for the reading section?