They are not dogs or pack animals. They are a herd animal so they respond to a strong, trustworthy herd leader that they respect. You need to step up and be a leader. Demand a quick response to pressure. Make her move over, come forward, back up -- just move her around AS YOU WANT. I prefer moving one back and over and around MUCH more than making one move forward -- as in longeing. When they are very apprehensive like yours is, they seem to view going forward as 'escaping'.
When you stop and back her up, use firm voice commands and then demand quick results. When you say "Whoa!", give her lead a jerk when she moves a foot. Then approach her again and let her eat out of a bucket of feed while you hold it.
Make sure you take ALL pressure off of her lead when she does the right thing. When you pet and brush, persist until she relaxes and then back off. Your lack of putting pressure on her is the only reward she needs.
The occasional feeding from a can (not your hand) is to get her easier to catch -- to get her used to approaching her without her leaving.
We have been going through this with a set of barely halter broke two year olds all this past week. Within 3 days of working about 1 hour a day, all are now catchable in the open, tie and stand still for grooming and are ready to turn out until we have time to start them under saddle. They were wild as deer a few days ago and now they stand with a hip cocked while being brushed.
Pick her hind feet up with a rope. A long rope with one end tied around her lower neck, looped around her back pastern and pulled forward with the hind foot in it will stop the leaning. When she stops leaning on the rope, rub her leg and release it by hand . A few times of doing this and she will pick her foot up without leaning.