answer:Fall of your senior year (or the fall a ear ahead of when you plan to enroll). Each school has its own deadlines and schedules, but it’s best to start getting applications in September and October. Apply to as many or as few schools as you wish, but research what the historical acceptance records are like. And apply to schools you really want to attend. Applications are generally the same, what do you want to study, what have you accomplished, what have you participated in, often an essay requirement. They want to get to know you as best they can. It’s been a long time since I applied, so I am sure a lot of people here will have more to tell you and up to date advice. Good Luck!