Stopping and starting...obviously essential, but practice practice practice until these things are second nature.
Don't put your foot down until the bike is stopped.
You will go wherever you look. So, if you see a bush in your way, look away from it, and you'll miss it.
Never, ever let someone pressure you into riding something you don't want to.
What worked for me as a kid, and worked for my kids, and is starting to work for my wife is to set up a little track and go around and around it. Include terrain that they are uncomfortable with...say side hill riding for example.... in the little track. Start small, and work larger. After a few laps, turn them around and go the other way so they learn how to tackle the obstacles in either direction, and don't get too attached to any one turn direction, cause there's times you need both.
I would also teach the value of watching out for others. Not to cross into other groups, etc. Teach her to follow the leaders lines, because as you know, sometimes just a little to the wrong side is not a good place to go.
Learning how to fall is a good idea too....if the bike is going over, push away from the bike.
Another good thing is to have her follow someone who knows how to ride..and try to copy what they do.
Teach her how to stand up! There are times when the last thing you want to be doing is sitting on the seat..

There may seem to be a lot of things to remember all at once for her. So just go slow, and adjust your pace based on how fast she picks it up. It's not hard, and kids learn really fast.