I had the exact same problem when I first tried FMQ. I received wonderful advice on this forum and it helped me lots.
Above all, practice! I made several quick sandwiches from old scraps and leftover batting - practicing over and over helped me figure out how fast to move the fabric. One suggestion I was given was to make sure that my needle speed was set for as fast as possible (or foot all the way to the floor) and that my stitch length and width was on zero.
A good pair of quilting gloves are a must.
I also learned to count slowly to 3 while I was making the curves and turns. Otherwise, my curves all feathered out on the back.
Post some pictures and you'll be able to get some great feedback.