if your horse isn't responding to the bit atm, bitting her up may help, as long as you are careful and don't get hard on her mouth. A baucher counds like a good idea, it's not a hard bit and it was effective for me when I needed that little extra strength on my horse.
If your horse is tense and won't give, another bit to consider would be a Happy Mouth. They have soft rubber, are fine for dressage (where I do it anyways) and they really help to soften the jaw.
Choose a bit, and perhaps try it with a lozenge in the middle. This makes it softer and also gives the mouth something to think about and ensures no pinching of the tongue.