List the areas you will be tested on. You may need to contact the professor or educational organization. See if they have a sample test or can recommend any study guides. The basic areas for the test could include algebra, geometry, probability and statistics.
Study the mathematical concepts in each of the test areas. Take sample tests to determine your strengths and weaknesses. Try to work on your weaknesses with utmost dedication.
Try to solve as many problems as possible for practice and to monitor your progress. You can contrast your present position with the last week, for example, and see what still needs work.
Make a list of mathematical formulas. Just before the exam, you may refer to the list to brush up your skills. For example, you may prepare a list for formulas of statistical functions. If you look at the list just before the exam, these would be fresh in your memory.
Take the test as confidently as possible. If certain questions appear tricky, approach them in the end. First answer all the questions you know. If time still remains, then approach the tricky questions. If you spend too much time on questions you do not know, you might not get to the ones you do know before time runs out.