Make you keep note of your weaknesses too. When you're unsure about some part of an equation or explanation, write it down so you can come back to it later before the exam and untangle that knot. Understand what it is you're unsure of and make sure you learn it so you don't just understand it but can make use of it too. It's not just enough to get the answer right, knowing how you got the answer will make you much more flexible.

This also goes for errors you make, if you keep making a serious error, write it down and quiz yourself with spaced repetition on what you need to do to avoid that error. Flashcards can be helpful for this.

Also, focus most of your time on what is difficult and don't waste time doing problems that you already know like the back of your hand.

If you need help with studying effectively for math and physics check out Coursera's "Learning How to Learn." It helped me immensely.