One of the best things I have learned over the course of my graduate degree is to talk to your professors. Build a rapport with them so that if you are struggling you can ask them for help
Examples: I've always been close with some of my teachers all through school, but I always felt that since I've been told I am very smart I have to do things on my own. This meant that if I was struggling I would consider myself lazy instead of seeking help. Now, I've had a busy couple of weeks and have been stressing about finals. So I just explained the situation to my prof and he gave me a 2 day extension!!!
So basically what I'm saying is, if you try your best (and you have good professors [not much you can do if you have a bad prof]) your professors will notice so that if you are genuinely struggling they are going to go out of their way to help you because they want you to succeed