See the link attached below for the free practice test; print it out and take it. Simulate a real test-taking environment as closely as possible and make sure to keep accurate time for yourself.
Enter your answers and access your score report on the College Board website. Carefully go over your score and evaluate your weakest and strongest areas.
Determine how much improvement, if any, is needed for you to have a reasonable chance of being admitted to some of your schools of choice. Another link is attached showing the average SAT scores of admitted freshman for different schools. Are you within or above the range for your targeted school? If so, you may not need a preparation course, though it is always a good idea.
Based on your score on the practice test, decide what you think is a realistic level of improvement you can hope to attain, and how much money you or your family are willing to spend on preparation. For the highly disciplined student, test prep books or online courses can be an economical option, and they have a history of yielding results for those who use them properly. Classes and private tutoring, however, offer more structure and specialized help, but generally at a much higher cost.
Now you are ready to start seeking out the SAT prep program that suits you best. If you are looking for a class or private tutoring, some of the biggest names include Kaplan, Revolution Prep and Princeton Review. These companies offer a variety of options at a variety of prices and have locations all over the country. Smaller companies also exist locally and often employ area high school teachers. For those already scoring well on the SAT and looking to go for a perfect 2400, there are services that are tailored more toward strategy than content. The important part of choosing among the options is making sure you know what you want out of the preparation and picking the program that can best meet your needs.