The important thing to remember is that on the grammar sections (I think they call them Writing sections), they love little grammar rules that aren't taught anywhere else. Any prep book worth its salt will ram those down your throat though.
Other than that, I find it hard to prepare for either the Math or Reading sections. Math you either know or don't, I've always said, but that was my weakest section, so maybe I did it wrong. And Reading will always have different passages than the ones you practice, so it's useless to me.
Oh, and essays. **** essays. 8/12 both times. Got one question wrong on all the other Writing stuff, but because of the essays I get a 750. *****es.
Of course, all of this is moot if you don't have other stuff going for you. I only got into 4 of my 6 schools, for example.
Math section was easy. Writing, too. Reading, though, for me is always terrible. I'm not a bad reader, per say, but I like more time to comprehend and some of the questions/answers are pretty ambiguous and I never can separate what I think from what they want to hear.
They let me on radio: http://gaberahamlincoln.blogspot.com/
I'm awful at math. Even Algebra confuses me.
More metal in Rock Band: