I used several different study guides. For overall test prep, I really liked Magoosh. Their math tutorials were excellent, the verbal prep was solid, and they provide video explanations for almost every practice problem. They also give you a daily schedule for which tutorials to watch and how many practice questions to do.
I also used Princeton Review's self-paced course, which was on the expensive side (my family was able to help me out with paying for it). The main benefit of the PR course is the eight practice tests. Their tutorials and drills for math and verbal were also very good, though I'm not sure they were great enough to warrant the high price tag. For a cheaper option, I'd recommend getting the PR book and accessing the two free online practice tests that come with it.
For essay prep, I highly recommend the resources ETS provides. Definitely practice with the pools of prompts that ETS has on their website, and check out the ScoreItNow service, which gives you a grade for eight practice essays. I was also able to get two free PowerPrep practice tests when I registered for the test, and I found those helpful.
In terms of my study methods, I tried to do some prep every day, and I did practice tests around the time of day when I would be taking the real thing. Knowing all the question types and doing multiple practice tests really helped me feel more comfortable on test day.