You write one main essay of 500-650 words to apply to college, and you send this essay to most of your colleges. You can send your resume to any colleges who allow it. Many colleges require that you write about 150-200 words on your most meaningful extra curricular activity, and many schools ask why you chose to apply to their school, so it is a good idea to have this "Why School X" piece ready as well. You can keep track of all essays you need to write here on CollegeMapper. Recycle wherever you can, but always proofread to change the names!
Start writing these essays during the second semester of Junior year, lightly. Hit it hard in the summer before Senior year and try to have as many of them as possible finalized before Senior year starts. Plan to edit each piece 5-10 times. Get outside editing help; no one can be their own editor!