Kid’s football is fun to shoot, but use a high shutter speed to freeze the action. Unless you have a high-end late model DSLR, use the centre focussing spot and crop: it will focus faster than the other spots.
Hardware: Canon EOS 1D MkIIN, EF 70-200 f/2.8
Exposure: ISO400, 1/640s @ f/8, 200mm
Post: crop, Increased contrast, sharpened.