Even if you haven’t made a preliminary list of colleges that interest you, it’s important to plan ahead in terms of taking standardized tests.
It’s a good idea to sign up for SATs and/or ACTs for the upcoming spring and plan a study schedule for yourself. Pick up a book or two about preparation for these tests and explore other options: classes, tutoring, study groups, etc.
Read up on scoring options so that you can decide whether you will take the tests again in the fall. Keep in mind, though, that early decision and early action schools will expect your test scores to be sent by the admissions deadlines, which are generally November 1 or November 15.