Compare the costs of the various prep courses. The cost of courses can range from $100 to several hundred dollars.
Examine what the prep course actually teaches. Find out whether the course emphasizes improving test-taking skills, math skills or writing skills.
Match what is offered in a course with your weaknesses. For example, if your graduate work will focus on math and you are weak at math, don't take a writing class, take a class that will help you improve your quantitative skills.
Determine how the prep course is taught. Whether there is individualized coaching or a classroom setting is a major comparison factor in prep courses. The cost of the courses typically varies depending on the amount of individual attention that students get when taking the course, with more attention costing more.