I've been using my son's rugby games to work on my sports photography. (This isn't my son) Right now I end up deleting about 90% of all the pictures that I take. Most of the problems have to do with focusing on the correct subject. I have a Tamaron 70-300 lens that doesn't focus very quickly, so I end up taking pictures just a bit out of focus. Also, I have learned that it is very hard to be in the right place at the right time. I have a new respect for sports photographers who sit in the endzone the entire game in hopes of getting a few good shots.