Sounds like she's at that stage in her training where the only thing that will help is lots of riding experiences. Miles and miles, months and months. Sorry, but there's no shortcut around this one.
Like any athlete, once you read the books and understand the rules, it's time to just get out there and do it. It will get uglier before it gets better (for both of you) but you are just now of the cusp of one of the most rewarding phases of horsemanship!
It's ok to be a bit fearful, not know exactly what you're doing (she doesn't either), so do it, learn, adjust it and do it again the next time.