How to work with a scared horse?

My horse had the same problem when I first got her. It took me a year working with her, I started by riding her very little, most of the time I just took her out in the yard and let her graze while I brushed her. Sometimes I didn't even brush her but sat in the yard and read a book while she grazed on a lounge line. I now have her to the point where I can pet her face, brush her face, hug her around the neck, spray her and use clippers on her. When she came to me she would have broken the cross ties and probably all four of her legs before letting anyone even turn the clippers on near her and she even went at my mom once when she saw her with the spray bottle. Now she just tenses up a little bit but other than that she's fine. I don't know about them men thing, my horse is only at the point where she trusts me. :/