For starters, I think that you're suffering from GMAT fatigue. So the most important thing to do is take a few weeks off from anything GMAT-related.
For me, I never really thought about a specific score. It just seemed impossible. How does one specifically aim for a 700 anyway? Do I need to make sure that I answer x number of questions correctly? How many upper-level difficulty questions should I get? There are a million other questions like these to think about and that's just exhausting. Instead, I just focused on one thing: doing the best that I could.
Goals are important, but don't obsess about some number; just do everything that you can to perform at your best on the test.