Tips and tricks for conquering the GMAT are few and far between. To do well on the GMAT requires an immense amount of discipline in order to minimize errors and ultimately answer questions efficiently vis a vis both time and mental capacity.
Here is how you should approaching your GMAT training:
1 - dedicate several hours to reviewing each question that you missed on the practice (or real) GMAT exam (if you download an exam report, you will typically only get a high-level readout of where you did well or poorly).
2 - following your review, identify your weak areas and focus on those areas when you train on your own.
3 - continue practicing problems of all types in order to ensure that your approach is balanced. Scour the internet forums for alternate solutions to problems that pose difficulty.
4 - seek help. As a Wyzant tutor, I seek to coach prospective Business School students on the strategies and tactics for achieving success on the GMAT. My students have seen 130+ point improvements by relentlessly focusing on their weak areas and adding structure and discipline to how they tackle this immensely conquerable test.
Hope this helps!