There are various online and offline sources where you can take the GMAT 2018 practice test for GMAT 2018.
GMAT 2018 practice test free
Most of the GMAT 2018 practice test and reference materials come with a lot of practice tests. Some books would even have tests based on the levels, where you can start with the easy question papers, and then gradually work your way towards the difficult ones. This would help you build up your confidence. The easy tests would show you which question areas you will need to focus on. After each test, read up on the ways to solve the questions that you got wrong, and practice that area well before you take another test. This strategy would help you strengthen your weak points as well as give ample practice in the areas that you are already strong in.
The official GMAT website also has links to download GMAT free practice tests.
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