To do well in this course you should attend lectures and discussion sections, read the book, and do the homeworks.
As the term closes in and you have a lot of work, it's tempting to skip meals or sleep less. Don't do this. It's impossible to do math or write bug-free computer programs if you are too tired. If you can't finish everything and you are getting behind despite studying frantically, you may need to reduce your load: speak to your instructors and/or advisor.
This is a hard class. Even if you have never needed help in the past, you may need it this term. Do not be shy about coming into office hours or asking questions (e.g. in lecture, on Piazza). Even if you fear your question might be "stupid," there are probably 30 other people who have the same question and they will appreciate the fact that you asked it.
The course staff don't bite. We remember when we took hard math classes and needed help ourselves.
If you think a homework problem is buggy or unclear, post a query on Piazza. If you think an exam problem is buggy or unclear, ask one of the proctors. Sometimes there really are bugs and you will be helping everyone by bringing them to our attention.
If you are having major problems, see our help page and also talk to your instructors and/or advisor.
Some parts of the assigned work must be done on your own. However, study groups can be extremely helpful for everything else. Your classmates can help you find mathematical bugs and, just as important, give you social support. Get to know the other students.
Homework is especially important. It's almost impossible to get a good understanding of the material (e.g. do well on the exams) without getting your hands dirty trying to work problems yourself. If you understand the homeworks, you'll probably do well on the exams.
Do not leave homework until the last minute. Math problems are much easier to solve if you have time to think about them. Also, starting too late may limit your chances to get help from the course staff.
Collect your graded work, look through the comments, read posted solutions. Make sure you understand any mistakes you've made. If you don't understand how you lost points, seek help from the course staff.