After spending a lot of money to sit in Graduate Record Examinations, usually known as GRE, one would wish to do as good as possible to get the admission into a prestigious institution for further studying. That is harder done than spoken. To get the desired success, one will have to know the strength and weaknesses that one possesses. Thus, one should know how to assess those. There are a few ways one can do that:
There are numerous websites and apps in the market which can help you in this regard. You will have to log in to those and take the tests. Many of those are free, but for a few, you might have to pay. Even ETS (Educational Testing Service, the organizer of GRE) has its own online practice tests (https://www.ets.org/gre/revised_general/prepare/powerprep/).
During the preparation for GRE, you should always give the exams on your computer since the central review will be on the computer. That way, you will be able to assess your computer navigation skills.
After giving each of the tests, go through the answers, and find out the wrongs and mistakes. Find out if the errors are just silly mistakes or conceptual errors. If those are silly, just go ahead and practice more, but if those turn out to be theoretical, it is time you grab the book again.
Find out how much time you are spending on the tests and how much you are spending on different types of questions. See where you are spending more time and which part is stuck. In the main exam, the time crunch might be an issue, so better work on it now.
Doing the previous things, you will be able to find which part of the exam is smooth as butter for you and which portion is stopping you. This is the time when you give a little more time to the bumpy parts.
One straightforward way to find where you are not doing well is just only by asking yourself, "Which topic do I hate the most?" Once you get the answer, you will know that you need to be better and just start working on it.
Create a track report to find how much your graph of progress is going up. You will know where you started and how far you have come. It would be better to keep track of every topic.
Studying with a group or in a study center can be beneficial as in this competitive way, you will find the lesser parts of your study syllabus and can work on it.
After doing these much and studying as hard as you can, I guess you will be confident enough to go and do your best to make a significant academic future—a bit of excellent luck.