What I did with my youngster was a pain, but it worked wonders. I work at the barn she is at so I went out about 6 times a day and put her halter and lead on petted her for 30 seconds and then letting her go so about 2/3 the time I came out to her I did not do anything with her. I did bring a pice of carrot or something about half the time but not always. It worked amazing in about a week she was coming up to see me when the first time it took over and hour to get her.
Once you have her caught this next time i would sit in a stable/barn with her giving her a bucket of feed and groom make it a pleasure and reward that she has been caught and come in. Have few treats and everytime u do catch her give her a treat it will take time but it will come. Always use her name, stay calm and dont rush and eventually she will come to you x good luck