The math and english sections are self explanatory. The analytical section is a bitch. You need to practice it. It is all logic problems. Like bob lives in a blue house, the man in a green house has a red dog, the man next to the green house has a cat...etc
You need to practice those problems as you get much better with it with practice.
I thought the math GRE wasn't much harder than the SAT math section, course, I made 800's on both so maybe im not a good source. I thought the english GRE was 10x harder than the sat english and if your down on your vocab because you could care less about english...good luck. It will be rough.