Research all of the various books that are out there for helping you with the SAT. Try to determine what books will offer you the most help in the areas that you are having trouble with in your practice tests so as to allow you to be able to focus on those areas for the test and use SAT lessons.
Make sure that you start to prepare long enough in advance of the actual SAT test that you will know what if any preparations that you will need to make in order to get the best score possible. See how long is recommended to prepare for the test and what kind of SAT lessons you should be doing.