After a quick look, my brief advice is as follows (and I'm not an expert, just giving you what I've gotten out of classes for my photojournalism minor):
Don't cut off limbs. feet, hands, arms etc...try to keep them all in the frame because most of the time, it looks awkward when you don't.
avoid getting sky in your photos. There are certainly pictures that having sky can make it better, and certain pictures are good because of the presence of sky, but in the photos like the paintball, you've sacrificed some lower bodies and possibly a more interesting shot overall by focusing on the upper portion of the body and a random assortment of sky and background.
Finally, when shooting sports action shots like paintball, It's okay to shoot loose and crop later. By shooting loose, you know you'll get all body parts and a good range of action in each shot. When you go back to edit and process, you can always crop out the unnecessary stuff and help the viewer to focus on the action you intended to capture.
I'm super tired and don't feel like proof reading what I just typed since it's 3:30am. Hope this was helpful!
