Since you asked for feedback on the forums:
You're actually pretty good for a beginner. That's sort of common courtesy to say, but in your case there really is no IMMEDIATE flaw that stands out blatantly. Most of what's off just comes down to your sense of perspective, proportion, symmetry, and line weight being underdeveloped.
Symmetry is probably the biggest factor, and it's most obvious on the bottom picture. Her left (aka the right side of the screen) eye and breast are both noticeably higher than their counterparts, and the opposite is true of her horns, despite her shoulders being even (though her left sleeve is shorter.) Her mouth and nose are centered, but her eyes are both pushed to the left a bit too far.
Like I said, not a bad start. It lacks polish, but it always will when you first start out, no matter how many principles you technically understand. What you need most at this point isn't actually critique from others, but to develop a self-critical eye for your own flaws.
