If you can work in a paddock (ie, somewhere confined, should she do something goofy and cause an unexpected dismount), that would be best.
I don't train a horse to canter from the walk, initially, that can come later, once they are comfortable actually doing the canter work. So doing a depart from the trot is fine for now.
When you get her into the canter, just to the perimeter of your pen, each way, once, for a start...don't worry so much about speed, or direction, just sit it, and let you and her get comfortable in the gait. I am assuming she has a good stop and turn on her by now? If she gets over exuberant, either push her through it, or use your stop or turn ability to calm her back down.
When you have her going around the pen 'smoothly' then start doing some circles each way. Refinement can come later, just get her going out foward, and calmly. Even leads can come once you get the 'grunt' work done, of teaching her to canter out willingly.
"The ideal horseman has the courage of a lion, the patience of a saint, and the hands of a woman..."