GMAT Strategy

I took the actual GMAT last Saturday and received a disappointing 540. I know I can do better as all of my practice test scores (Kaplan & GMATPrep) ranged from 550-600. Now I'm going back to the drawing board and here is what I've come up with:

The first time I was studying questions in the OG 11 and Green OG book. I read every explanation and tried to work with questions that were challenging but I was still able to do. My Quant. score on the GMAT was at the 30 percentile, so this must not have worked. I felt the GMAT was very hard and I struggled with most questions. Its weird because I was confident I could handle the Quant. section well. Admittedly, I messed up with timing.

I've pretty much exhausted all OG book questions, Kaplan books, etc., so my fresh resources are running low. My plan now is every morning to take half of a MGMAT CAT.

My reasoning for this is that I have no problem with overall stamina, but rather, just struggle with time in the Quant. section. I got a 6.0 on the AWA, so I'm not worried about the either.

So, for example, Monday I'll take a full, timed Quant. section, try to review in the afternoon, then next day take the Verbal section and review. If the review in the afternoon doesn't work I will try do that on the third morning.

With this plan I'll be taking a full practice test every three days. I'll also be working a great deal on my timing which needs work. Also, I think I should be able to develop a better understanding of certain questions with this repetition. I feel like I have a solid foundation in everything the GMAT tests, I just have trouble putting it all together sometimes.

Does this sound like a solid plan? I feel like this is the only thing I can really do. I'm planning on re-taking the test in September, so I don't want to take any time off or anything.