I think the most efficient way would be:
1. Take out anywhere you wouldn't go. Every year someone comes on here talking about how they don't want to go to the school they were accepted at. Don't be that guy.
2. Take out the most competitive schools (read: JHU, Yale, Columbia, etc.)
Not saying you don't have a shot at those places. But they are where your chances are the slimmest, so they are the easiest targets to take off the application list.