It is great that you are out and about snapping.
Being honest, these do look like snap shots, but you have potential.
Try to think about what you like in a photo, and as someone else said in t'other thread, make the photo in you head, and then try to make it happen.
1/ - nice group shot. I think this would have worked better if you were more to the left, so that all the horses were looking at you, almost like in a circle. ALso think about the height you are taking the photo from, If you crouch down, with all the horses looking at you, they look taller, and you get more of a sense of perspective.
2/ - This is probably the most worst. Ther is npt much happening, and the stuff to left of the horse in the backgound is distracting. Again, being side on does not give much connestion to either the horse or the rider. Being more in front of the horse so you get more of the horse and riders faces woyld be better. You also have a big zoom on your camera. Don't be afraid o get in close and not get all the horse in.
3&4/ Good capture of the action in both these. It would be noce to see where the horse is coming from/going to though, to get a sense of persepctive. You also sem to be looking down on the riders, making them look small. Again shooting from lowere down, lying down if you have to, will make them more imposing, and more impressive. With both these, you are shooting into the sunlight. THis makes the background overexposed (too much light) and the horse and rider underexposed (not enough light). You also have the shadows on the water, which are quite nice. If you were on the other side of the horse, with the sun behind you, then the horse and rider would be nice and bright, giving a better photo.
5/ This is the best of the bunch. You have caught the moment perfectly as the horse is in the air. I would like to see a closer crop, giving more detail of the horse and rider,this time, you have the source of light coming from your right, with the jump in the shade. It is the sunlight hitting the background that is much brighter, hence the "blown" - overexposed background. You need to learn how to use the manual controls more I think to sort out this, although if the sun was behind a cloud at the time it wouldn;t be an issue, so unlucky on that front. The angle is good, you can see enough of both the horse and rider to be interested.
HTH, and don;t take what I said as gospel, I just say what I see, and someone will correct me in a minute.