Most often, in a math test, you solve problems, such as formulas, equations, word problems, logic questions, and so on. The best way to prepare for a math test is to practice sample problems that are likely to be on the test.
When studying, practice all types of problems, but focus especially on the problems for which you didn't receive full credit in your homework, quizzes, or in-class assignments.
Be sure to check your work. Even if the instructor doesn't require it, show your work on scrap paper so that when you review your answers, you can check each step of the equation from your work.