This business is similar to
a tutor, but it specifically deals with the SAT only (or you can offer
other specialized tests such as the GED or LSAT). You should have taken
the test yourself, and you can advertise your (hopefully) high mark in
your marketing efforts.
You can offer one-on-one tutoring,
or some tutors will offer a mock-test to several students at once.
This is a pretty static field,
meaning if your technique works, there is no need to change it for future