Domesticating a stray/feral cat

Question
I live in the country, and recently moved into a new home. There were about 5 or 6 strays in the immediate area. One or two I took a likng to. I have been care to feed just those two so they know the food is for them, when the others arrive I pickup the food until a later time when it is just them, it seems to have worked as they are parked outside my door every am and pm like clockwork. I even have gotten them to come through an open door to eat as long as I am at a safe distance. One time I was able to close the screen door behind one, and she kept feeding, however once the food was gone she went bonkers and jumped up onto a windowsill and jumbled my venetian blinds in the windows. She still shows up every day and will still come in at a safe distance to feed, but is very skittish if I get up or move. Is there anything else I can do advance the domestication process?

Answer
Honestly, you're doing everything you should be. Ferals take a long, long time to warm up to people. One thing I could suggest, if you're not already doing this is when she is eating keeping moving bit by bit closer. She will run, but will come back. Just keep being patient and you will see progress. The fact that she keeps coming back shows that she knows you'll be there to feed her and that's gaining trust. I give props because not to many people have that much patience and persistence. I personally love taming ferals. But it was easy for me because they were in a shelter and I was able to use a fake hand to warm them up to me. Now if you can luck out and mimic that kind of setting, with a cage, crate and get a fake hand or similar, that's always an option. But I would stick with what you're doing. Let me know how things are going.