The GMAT is a test of your math and verbal skills AND it's a test of your test-taking skills. So, taking several practice tests is an important part of your prep. This will help you build your test-taking skills, and it will help you identify any remaining area(s) of weakness.

While analyzing your practice tests, there are four main types of weakness to watch out for:
1. specific Quant skills/concepts (e.g., algebra, standard deviation, etc.)
2. specific Verbal skills/concepts (e.g., verb tenses, assumption CR questions, etc.)
3. test-taking skills (time management, endurance, anxiety etc.)
4. silly mistakes

For the first two weaknesses, the fix is pretty straightforward. Learn the concept/skill and find some practice questions to strengthen that weakness. To focus on one topic at a time, you can use BTG's tagging feature to isolate one concept. For example, here are all of the questions tagged as statistics questions: https://www.beatthegmat.com/forums/tags/ ... statistics
See the left side of that linked page for more tag options.

If your test-taking skills are holding you back, then you need to work on these. For example, we have a free GMAT time management video at https://www.gmatprepnow.com/module/gener ... es?id=1244.

Finally, if silly mistakes are hurting your score, then it's important that you identify and categorize these mistakes so that, during tests, you can easily spot situations in which you're prone to making errors. I write about this and other strategies in the following article for BTG: https://www.beatthegmat.com/mba/2012/09/ ... n-the-gmat

Cheers,
Brent