I took the GRE back in the late 1970s. I was terrified and could barely sleep the night before. I remember finishing the first section and looking around at the other test takers. I was the only one finished. I rechecked all my answers. I looked around. I was still the only one done. I knew I must be doing something wrong.
Turns out that I had the highest score of any of the applicants to my school that year. I thought the GRE was easier than the SAT, probably because a number of years filled with learning experiences had gone by between graduating college and going to grad school. Not so true for a lot of the other hopefuls.
My study technique was to go over and over those books with sample tests. If you get the rhythm of the tests down, they are easy. Oh, and since I am a math phobic, I hired a friend to go over basic math problems with me, explaining 7th-grade math. I ended up being (just barely) in the top half. One of my professors told us she was in the bottom seven percent in math but still got into journalism school. The social sciences don't need you to be a math whiz, either.
A lot of questions give you hints. If a blank answer counts as a wrong answer, answer everything. If you have no idea about the answer, try to narrow your answer down to two, so you'll have a 50/50 chance.
You probably already know this stuff. You just need to get comfortable with the test.
Good luck!