Enroll in a GRE prep course. There are many courses to choose from in various formats ranging from individualized tutoring to online, self-paced learning. GRE courses can be expensive, but the knowledge you gain will almost certainly raise your score. If you go the self-taught route, you may miss key information about which formulas and problem types are most commonly on the test and how to spot and correctly answer tricky questions.
Buy GRE math review books. Algebra textbooks contain more information than necessary, but the specialized books contain the algebraic operations you must learn for the GRE.
Familiarize yourself with the algebra subjects tested. The algebra section of the GRE covers much, so you must understand factoring, exponents, coordinate geometry, quadratic equations, scientific notation, inequalities and several other operations.
Take practice tests online, in conjunction with your prep course or work in your review books. Review which algebra problems you missed and target your studying to those areas where you need the most practice. Ultimately, you should spend time reviewing all tested material, but hone in on your weakest areas.
Work problems in your weak areas whenever you have spare time. Make or buy flashcards with sample questions and formulas to carry with you wherever you go. The best way to learn algebra for the GRE is to work problems and review material until you feel confident.
Take another practice GRE test after you feel comfortable in all areas of algebra. Simulate actual testing conditions by adhering to time constraints, clearing your work area of all related materials and taking the test on computer. Review your algebra score and continue to review until the day before the test.