Some of your problems look like what I call the swoop factor on curves. There seems to be a natural tendency to swoop on curves. That is to go faster -- I think if I were drawing I would do that to try to keep the curve consistent and smooth. That spells a lot of eyelashes and inconsistent stitch lengths in FMQ. Fight the swoop.
By the way, some of your stitching is quite nice and you are doing very well for such a novice.
Keep up the good work!