I generally will help out schools, booster clubs, churches, and civic groups. In a small town these are the areas that give connectons to future caterings. Schools have a graduation every year. There are X amount of customers per graduating class. Booster clubs involve the entire school school system. Church congregations are a great way to build caterings.
I help with more than a donation. I do a "cook" for the athletic and music booster clubs and a couple other school groups each year. We donate our time, vend it just like we would for a normal vending. I charge them cost of meat and supplies. and I have some HS students help me serve and take money. Once I even worked with the foods class. We seasoned the meat early morning, cooked it all day, and by game time it was ready to serve. Two area/local newspapers were there for that one! Ultimately this donation of time and cooking will have pay offs.