Since you have only about a week left until your exam, to improve your quant and verbal skills, you may find it helpful to engage in focused practice of each individual quant and verbal topic. For example, let’s say that you want to practice Number Properties. You can do so by answering 50 or more questions just from Number Properties: LCM, GCF, units digit patterns, divisibility, remainders, etc. As you do such practice, do a thorough analysis of each question that you don't get right. If you got a remainder question wrong, ask yourself why. Did you make a careless mistake? Did you not properly apply the remainder formula? Was there a concept you did not understand in the question? By carefully analyzing your mistakes, you will be able to efficiently fix your weaknesses and in turn improve your GRE quant skills. Number Properties is just one example; follow this process for all quant and verbal topics. Also, you may find it helpful to read this article:

https://gre.blog.targettestprep.com/gre-test-day-tips/

Feel free to reach out with any further questions.

Good luck!