How do you catch a horse that runs away from you in the paddock and when you go near it it bucks?

My horse used to do this to me. I would get a bucket of grain and shake it and usually they will come trotting to you. When the come, just give them a bite of grain so they don't get sick and you reward them for coming to you. Sometimes just hold out an apple or carrot and they come.
I don't know whose stupid idea it was, but NEVER put a blanket over a horses head unless they are fully restrained. If you put a blanket over the horse's head it will become either frightened or mad unless they have at least a leadrope on. It's like if someone threw a blanket over you when you're mad, you'd be even more mad!

I would be cautious about going into a field with many horses with a bucket of feed as you may risk being trampled. I would tack some treats or some feed in a pocket out with you and persist with approaching the horse in a calm manner, avoiding staring directly into its eyes, which is regarded as a threat. Don't approach the horse from the rear but rather from the side. If it wears a head collar then attach a small length of rope from it so that it it easy to grab when you get near enough. If they are in a field with many others, if possible get all the others in first and then get in the one you have left til last, they are usually keen to come in then. When they come in make sure they get something nice, like hay, and are not always ridden or worked immediately. Try and remain calm and persist in approaching the horse.