This thread is BEST THREAD.
Also, the clothing in particular looks extremely flat. Try having a look at clothing bends and folds - once you start to get your head around that, things will improve dramatically!
Eyes look good, though!
The self portrait is generally good, but the top of the head hairline/shadow thing looks weird and blodgy. If that's a dark shadow, it looks really out of place given how well-lit the rest of the face seems to be. Otherwise this is pretty cool
The trick with pony jaws also comes down to line thickness. Look at some screencaps: the nose part is really thick, and then thins out to a graceful curve down along the chin that tapers out. Also merge the nose into the eye a bit more; the curves follow, and it makes the pictures look more harmonious.
The wings, however, look fantastic.
And good luck to everypony! This may seem hard at first, but it's absolutely worth doing! You won't believe your progress if you stick with it.