When it comes to sports photography, other than being able to capture the peak of the action, one of the biggest things that can make or break a photo is the background. A lot of times Ill see a sports photo that has amazing action but the background it so distracting it takes away from the action that is taking place in the frame.
One of the first things I do when I get to a new venue or someplace I don't shoot much is take a walk around the field and take a look. I think to myself if I shoot from this spot what is going to be in the background? A lot of times I have found by moving a few feet left or right or changing sides of the field I can instantly improve what my backgrounds look like.
Another think that I do is I shoot with wide apertures. I have found that f2.8 to f-4 is a good range to both allow enough light into the camera to maintain a high shutter speed but to also create good background separation in the form of bokeh. Background separation will do two things for you. One it will "clean up" your backgrounds so they aren't messy and distracting and two they will make the action you are shooting stand out and pop.
Now I know a lot of times its not possible to get a nice clean background, especially at high school games. You just have to pick a background that is the least distracting and will not take away from the images.
Another thing to remember is backgrounds (and foreground) can also add another level to the photographs. There's nothing wrong with incorporating the backgrounds into your photos if they add to the photo.
Check out the video above for my explanation and some examples.