Four months is a very reasonable amount of time to prepare for the GMAT, depending on how much time you have to study each day/week. Here's what I would recommend:

- Start with a practice test (either GMATPrep, or any test prep company's). Analyze it in a lot of depth, and compare it to the practice tests you took last year. In which areas were you weakest? Strongest? Fastest? Slowest? Decide which topics and question types need more of your time and attention.

- Study those areas topic-by-topic, and practice each topic with OG problems. For example, read the chapter (from whatever guide you're using) on SC subject/verb agreement, then go do a set of problems in the OGs that relate to that subject.

- Try to do a little bit each day. Don't save it all for the weekends! One hour each day for 5 days will allow to to build and retain information much better than just 5 hours in a row on Saturday.

- Once you've covered all of the topics, practice your skills with random timed sets and practice tests for the last 2 weeks before the test. Focus on pattern recognition. How could you recognize what's being tested? Are there any shortcuts you could use? How does this problem connect to other problems on the same topic?

- Analyze your data from the random sets, and go back to any topics that need extra work.

As far as your study materials, you have more than enough! GMAT studying is all about quality, not quantity. Good luck!

I'll echo C's points above and just add a few additional thoughts....

Her point of quality over quantity can not be overstated. The goal of this entire process is to consistently make your areas of focus narrower and narrower. Once you feel like you've mastered an area -- move along to another area that you need to master. As C said, four months is plenty of time, but with your target goals -- you'll have to work to get there.

Since you are just starting out, I'd love to point you in the direction of a few articles we've written that really lay out the basics of how to build a study plan. I'd encourage you to take a look and then shoot back to me with any thoughts/questions.

https://www.manhattangmat.com/blog/index ... an-part-1/
https://www.manhattangmat.com/blog/index ... an-part-2/

Good luck!

-Brian