PREPI started prepping at the beginning of October 2023. Main materials used were:
- Manhattan prep books: all the quant, all the verbal, integrated reasoning and essay (just at the beginning for the fundamentals. They are great books but they are not enough)
- The wiley question bank for OG questions: OG questions are the best and only bet for verbal questions. You have to be very careful what you use for verbal because you absolutely don't want to "pollute" your verbal "sense" with unofficial sources. I cannot begin to tell you the number of questions that did nothing but confuse and confound me all in the name of teaching some obscure point that no one is going to ask you in the GMAT exam. I ditched unofficial verbal questions (apart from questions I saw in manprep mocks) and I think it helped.
- GMAT Club tests: I really wish I had started with these for quant. They are very difficult but I think they're the only thing that will get you used to the level of difficulty in the actual thing. But don't quote me on this, I am obviously not a quant guru 
- OG Mocks 1 to 6: scores ranged from 690 to 760. The 690 was on mock 6 just before my first attempt and that wasn't a great feeling. I retook mock 6 on the weekend before my second attempt and got a 770
- Manhattan prep mocks 1 to 6: scores ranged from 640 to 740. Taking these is the best way to replicate that terrible "fish out of water" feeling that you will get in the actual GMAT when the questions start ramping up in difficulty
- Target test prep free trial during the 3-week period between attempts: you can get 10 days free if you have enough gmatclub points. I mostly used the question banks but I can see why people find it useful throughout their prep.
LUCK AND RESTI gotta say that there's a lot of luck involved in this exam so if the first time doesn't go well, get your esr, keep your chin up and keep going! For my first attempt, I was so nervous. I had worked myself up into such a frenzy that I was sleeping 2 hours a night the week before. I even had to ask the doctors for advice all in the name of GMAT. My advice is to try and unclench somehow. Do something else: go outside, pick up a new book, listen to some new music. There's more to life. This time, I let it all go: there was no special breakfast and no special routine. I spent the night before watching Netflix and I slept better.