GMAT quick Tip
I don't know who has to hear this, but I really believe you should do your mocks using an erasable scratch pad like the one you'll get on your official test rather than pen and paper.
Not being used to the scratch pad properly and finding to adapt to it on the last minute under pressure can be challenging.
Also it's not as good as using paper and if your handwriting is as bad as mine, you might end up making stupid mistakes. Like your 5s looking like Ss or 2s looking like Zs