Like with all things with horses, you want to break things down into little steps and make sure each step is correct before moving on to the next. If I were in your shoes, I'd start out by hanging out when they eat. If they won't approach their food with you there, step back a bit. If it's still too close, step back further. When they seem OK with it, then just stay where you are. Don't get any closer that day. The next day, try a bit closer. Etc.
Actually, what I did with my Teddy and what I do with other horses that seem afraid is to make myself very small, both physically and mentally, and try to approach with cookies or some other treat. Don't look them in the eye. Don't stride right up to them. With Teddy, for instance, I couldn't even approach him in the pasture at first without him trotting off. So I figured out where his personal space bubble was, and stopped there. Then as he grazed, every time he took a step, I took two steps: one step forward to stay with him, and one step closer to him. After about half an hour I had gotten to within 10 feet or so and he started to look like that was too much. So I squatted on the ground and held out the hand with the cookie. He was a little nervous still but not as much, so he went back to grazing. So I took a squatting step closer to him and held out the cookie again. Eventually I got close enough to where he came over to see it. He ate the cookie, I said "good boy" and just left. The next day, similar.
Someone else here recommended just getting a chair and a book and going out to sit in their pasture. Depending on where they are mentally, you might not even be able to face them. Just bring the chair and sit and read for a few hours. Eventually most horses will come over to investigate. You could include treats in this or not.
To me, it's just similar to any feral animal -- bring food, act non-threatening, and don't rush things. Be able to read their body language.
I don't know if that's the "best" way, and it's certainly not the way that most trainers would do it, but it's how I would do it. Don't go to them. Make them come to you. Make them WANT to come to you.
"Saddle fit -- it's a no brainer!"" - random person