Our first inquiry letters had a good picture in the upper left. On the upper right was a small box with son's name, year of grad, birthdate, school, position, left or right hitter/pitcher, ht and weight. The body of the letter was hand written for the initial "i am interested in your school." My son liked to add a "Go Cardinal!" or whatever the name of the team was for the school. We also formated a player profile with stats, phone numbers, references, etc. If it was a school of high interest, we'd send that along with the inquiry letter. We'd always fill out the questionaire that followed, though. I kept the player profile in my document folder in my computer and we'd update it. Once we got a league schedule, we'd send that and add showcases, camps, etc.
It's quite a little kitchen table business. Get a good filing system going. keep track of who wrote back, whether it was a personal response or whatever.