They are the only questions which are truly representative of what you'll be facing on test day.
Solve each and every question from the ETS official books and the Powerprep tests. book of Practice Problems by Manhattan Prep Official Verbal Practice Questions by ETSĥ lb. Official GRE Test 1: 166V/170Q (T - 1 Week) Official GRE Test 2: 160V/169Q (T - 2 Weeks) Powerprep Test 1: 165V/169Q (T - 3 Weeks) I made sure I completed all the questions from every ETS official source available. Most of that time was devoted towards solving practice questions for the verbal section. I only spent 30 days studying 2 hours per day on an average. The only mocks I took were official ETS mocks - 2 Powerprep mocks and the 2 from the official book. After studying for 10-15 days, I took the Powerprep I mock and scored 334. Hence, I decided to shift my attention towards official ETS material. The actual ETS questions didn't solely rely on vocabulary and it wasn't a cakewalk if you knew all the words in a question, unlike the Manhattan 5 lb book. However, when I tried the actual ETS questions, I found out that the type of problems were significantly different from the 5 lb book, at least for Text Completion and Sentence Equivalence. I did practice questions fron the Manhattan 5 lb book for the verbal section for a week or so to try and build my intuition for the verbal section. Most of my preparation was focussed on the verbal section since I was struggling with verbal a little initially but my quant was near perfect. I didn't think it was possible for someone like me to ace the GRE. I generally held 330+ GRE scores in high regard, assuming that scores as such were incredible feats to achieve (even though I did understand that the GRE fit in as a small piece in the larger scheme of the graduate admissions process). Although I was a little pessimistic before beginning my preparation, things went suprisingly well for me.