Hi Isha,

The best advice I can give you is to skip the questions you don't know, and come back to them at the end if you have time. 

When I take a test, I pretend like it's a game where I'm trying to score as many points as possible. It doesn't make sense for me to spend 10 minutes on a problem that I don't know, just to possibly score a few points (assuming I even get it correct). It would be better to use those 10 minutes to finish several easy problems that I know, thus scoring more points than finishing the one problem

Let me know if you have any further questions!