In the interest of helping you improve, I am going to be honest.
Almost all of those are deletes beyond the technical errors like horizons, white balance, timing, focus and cropping.
You typically want the face of the person in control of the ball. The only real keeper would be the PK, but that needs to be cropped tighter to get rid of the background. Speaking of the backgrounds, unless something is adding to the photo or the story the photo is telling, get rid of it.
1- No face, extra player on the left, distracting background. What is going on here? Did he miss-control the ball? Did he just receive a cross and is trying to settle it? Is he pulling it back or doing a Cruyff to shake the defender? Too many questions.
2- The keeper caught the ball, nice. Where is the action though? This could be a neat sense of place type shot if the stadium was bigger. But as it stands, the stadium in the background is ugly.
3- Too loose because the timing was off, but going past that, where is the action? Did someone take a bad touch? Is the ball in the air because it was chipped to them? Too many questions again.
4- Their legs got chopped off. But where is Lenhart's face? Again, what happened here?
5- Good timing. This is a good stock photo. Crop the background out though, it only serves as a distraction.
6- Decent timing. No faces though and out of focus where the action is taking place.