The advice given here is great and given by folks with much more expertise and experience than I have aquired. With that said I will share our experience. The larger camps often have multiple coaches and often there are activities going on at more than one place/field at a tiime. While the goal is to impress with performance - the coaches must SEE the performance to be impressed. A communication prior to camp with a polite reference to any two way communication upon arrival may increase the chance that the coach makes an effort to see a player at the right times - to get on the "must see at this camp session list". In our experience there is a list.