As with all things, practice makes perfect. It’s impossible to expect to be great your first time doing anything. Even seasoned sports photogs still have a learning curve when shooting a new sport. The more you cover a specific sport (and it helps tremendously to already have an understanding on how it’s played) the better you can anticipate the action and you know what you want to get pictures of instead of just trying to shoot any random action happening in front of you.
As far as keepers, as already mentioned that’s a lot. Obviously different people have different definitions of what makes a keeper (for some it’s as long as it’s in focus, others are much more specific like peak action/ball/face/no body part cut off). I’d say 10% is a great ratio to be at, and like mentioned above when you get to know a sport and know what kinds of photos you want, your overall shot count goes down and your keeper rate goes up.
Pic-time has a free option, a great interface, and implementation for photo sales and prints. Dump all the pictures in there and send one link out to everyone.