Replying to AP Chem PRE help

Alright, so i have school starting wednesday, and im in AP Chem. I did baller in chem last year, all 3.5's and a 95 on the regents (my teacher gave me a 4.0 for the year).
But i forget shit over the summer.
So we have like 700 questions in a chem packet to do in two days, and we have a cumulative test of last year in the second week of school. We also have forumal writing test in the first week of school

So i need your tips or memorizing forumals a shit. The formula writing test is all memorization of polyatomic ions and normal elements and their oxidation numbers. I need to memorize this stuff well. I did it last year, but i was in learning mode.

Also, i just need to remember a bunch of formulas that were on the regents chem reference table


Any tips to memorizing? shit i should remember that's really specific or confusing?

thanks