Answer:
If you have a horse that is a problem to catch there are a couple of things you can do. If at all possible keep him by himself if he shares a pasture with other horses. The ideal would be to put her in a smaller paddock where she has a common fence line with her friends. When she has a much smaller enclosure she will find out very fast that she can't avoid you. The larger the enclosure the more she can run you around.
A horse with a halter can be much easier to catch. But if you opt for this you must not use a nylon halter. Nylon halters won't break and your horse could get it caught on something and injure herself. There are 'break-away' halters that will snap if much pressure is put on them. Or a leather halter will be safer because leather will snap or break with very little pressure also.
And last, try not to get angry. Remain calm even if you don't feel it. Always praise her when she lets you approach and give her a treat. Most horses can't resist a kind word and a snack.