Greedy with study resources ended up with disappointing score

One very important point in GMAT that everyone should have been telling to everyone with emphasis is that you get punished more for getting an easy question wrong than getting a hard question wrong. That has a significant meaning in GMAT. You do not breeze past >700 level questions when you are at >700 level. Being at >700 level means you can solve with ~100% accuracy easy questions, >85% intermediate questions and at least more that half of >700 level questions. I don't know about others but I am not able to solve more than 60% of 700 level questions within 2.5 minute, those questions you find in this forum or any other major preparation companies. With that accuracy I always scored above 48 in quantitative section. In verbal section, I am not good. I took GMAT recently and got score of 710 (q50, v36).

Let me list you very important points those I found are key in GMAT:

1) Go thoroughly through the basic concepts before jumping into >700 questions. Doing tough questions a lot is not going to help you. Having thorough understanding of subject gives you ability to solve easy and intermediate questions with high accuracy. While going through basics, practice one topic at a time and practise easy first then intermediate level questions. Not mixed questions. Not tough questions. GMATClub's 'questions by difficulty level post' is a great page for practising in this way. Once you finish all the topics this way then you can start doing mixed questions from OG as well as official CATs. And then if you fancy you are ready to do tough questions, start solving them.

2) You don't need to do too many full time CATs. After going through basics give official CAT1, after about 30 days give official CAT2. Then, within 10 days before actual test re-do the CAT1 and CAT2. It is very important that you sometimes spend about 4 hours straight practising. Having stamina and endurance for being in mentally challenging situation for more than 4 hours is very important and for that you need to practise by mimicking the tough situation of actual GMAT.

3) Have the ability to figure out toughness of question quickly. Again, You get punished less for skipping tough questions. Skipping tough questions gives you extra time for others. I skipped few tough questions in my real GMAT's quantitative, had more than 5 minutes at the end and still got 50.

4) Eat balanced diet, sleep 8 hours and exercise. Choose morning test time if possible. Exercise but not too much before the test to increase the blood flow.

Plus: Increase your reading speed. Having better speed than 350 words/ minute with >80% comprehension is important. If you are not that good then start reading at that speed some long novel like Crime and Punishment. At first, you won't understand much but by the time you finish the novel you will have improved your reading speed by quite much.