The quilters here have given you some great pointers. A few more tips that might help -- speed up your movements a little bit. The slower you go, the more jiggly your movements will be. And don't look at the needle or the hopping foot. Look at the line ahead. It is sort of like driving a car - you look ahead at the road not at the steering wheel. Your hands follow your eyes.
Don't be hard on yourself. You are the only one who sees the line of the panto. Everyone else only sees the quilting.