If she gets 'stuck' doing the circles, make bigger circles so that it's not too hard. Practice hurrying her feet around on the circle so that she doesnt slow down while making the turns. If you're walking, hurry her into a crisp walk, if you're trotting, hurry her trot around the circle. That's also a good submission exercise and it will get her more focused on the job.
If the cue to push her over isnt working, move on to something else.
If she pitches a fit when you ask her to turn, it's a great opportunity to build a fire and then put it out. The more 'fires' you put out in a horse, the better they get. If you avoid the fires she wont get truly better.
If she threatens to rear, make her move her hind quarters over. A horse cannot rear if their weight is on their front end.