I am in no way good at hand quilting but this has helped me-
a. good needles and short ones John James and Richard Hemmings
b. very loose in hoop (like the cat slept on it) I put it in the hoop pul it thight, loosen the hoop and push the back of my fist on it and then thighten.
c. Mountain Mist batting
d. not too thick a muslin on the back
e. "I can achieve more if I do a "two-hand" single stitch-- i.e., all the way down with the right hand, pull it through on the bottom with the left hand, then do an "up" stitch from the bottom with the left hand, pulling all the way up with the right hand. BUT this takes FOREVER. And frankly, I think my stitches are less consistent and a bit messier." Copied from another post but I have the same experience.