Diane Guydinski [?spelling] calls it mittens and Mickey Mouse ears. Some other quilters just practice what comes to mind: flame-like, flowery, or angular. If you are still learning then don't worry about crossing the lines. It is too stressful.
Try drawing it several times before you actually do the quilting. If you want use an air erasable pencil to draw on your quilt top.
I think you are just tensing up too much. Have fun with it.
ali