They often vary from college to college. Number and type of recommendations required. Interview deadlines and locations. Write every important deadline on your calendar, including federal financial-aid deadlines. Maintain or continue to improve your academic standing.
Most colleges look unfavorably upon an applicant whose grades are falling.
If one of your grades is falling, write a letter of explanation. Continue visits to the colleges you are seriously considering. Update your college-planning portfolio. Be sure to add recent achievements and new events that have occurred. Subject Tests as you wish, but no more than three per test session.