I'd suggest alot of groundwork before you graduate to riding her. I start all my horses that way, and I don't get on until I'm certain I've earned their respect on the ground first. Everything centers around respect and trust in a relationship between man and horse (or woman and horse, lol.)
Personally I enjoy the Pat Parelli games that you play on the ground. They are fun for you and your horse, and they teach respect, and get the horse moving in all the directions you will need it to from the saddle. You can always buy one of his books, but searching on the internet for articles is cheaper and he is well known, so not too hard.
Also Clinton Anderson's lunging for respect methods are great. Here is something to try:
1. Make sure you can touch the horse everywhere on its body without her becoming concerned. This shows she trust you enough to give you access to her most vulnerable spots (kill spots for a predator.)
2. Move her haunches away from you by applying pressure. Start with light, rhythmic pressure and let it become more intense until she gives. Work so that you can move her with just a light touch from both sides. Do the same with her forehand, moving away from you. Again, repeat this on her chest to get her to back away from you. Practice the "start light and get stronger" method and ask her to come towards you on a lead rope. Get her moving her haunches, forehand, and backing up just by stepping towards that body part. If she doesn't move when you step towards her, gently wave a hand or rope. Wave it stronger and stronger until she moves. This is the same concept as touch, but this is step higher, using only signals and body language to get her to move. She'll gradually get it and soon you'll just be able to take a step and she'll respond. This is a basic overview of a few of Parelli's theories.
.3. Longe her, but don't do mindless circles. Do a few one direction, stop her by stepping towards her haunches, and putting pressure on the rope, utilizing the move away exercises you practiced in the step before this to get her to stop and face you. Go the other way. Vary your laps so she doesn't anticipate changes in direction. Try and get her to longe between you and a fence, creating a gap that she has to go through. This tests her trust because she'll be running through what appears to her as a confined space. Longe her over poles on the ground, or small jumps....Get creative, just stay safe. Get her to load in a trailer from off of a lunge circle at the walk, etc.
When you get her doing all these things willingly and happily, you have a good base for riding. If you're still having troubles, seek some more help and re-affirm your line of communication.