Upload & Sell: Off
Colors and exposure looks okay and you've caught some peak action of what are really more stock-like images. Now, what could you tweak to make these (and future posts) just a bit better? IMO, it would be cropping out some of that wasted space. In this set, for example, you would not only be cropping out wasted space but some of the distracting lines and shapes at the top of several.
Specifically, 1, 4, 5, 7, and 8 all have space at the top PLUS space that has a bunch of distracting lines and shapes (#8). With some like #1, 7 and 8 a tighter crop off the top won't get rid of all the bleachers or shapes, but it will make them less distracting. With a tighter crop off the top of #4 and 5, however, you take much of that distracting background out of the image as I've shown below. (As always, just let me know if you have a problem with me cropping your images and re-posting here.)
Again, there's nothing major wrong with these images and I'm sure there are a lot of people who would be totally happy with them as they are (including parents who might be buying them). But for me, I opened the thread and the first thing I saw at the top of image #1. Had it just been that image I'd probably not have said anything, but since there were several I thought this might give you something to think about.
Good luck this season!