Many don't like the manner in which I give a critique but you asked.
Your approach is "sloppy". Finger nails are probably too long. When you rest the fingers on the leather they make nasty marks. Your drawing may very well be alright, you simply are not following the tracing. YOUR TECHNIQUE IS TERRIBLE, WHICH YOU ALREADY KNOW. LOL
Those things said: It appears you are trying to begin at the end instead of the beginning of Leather Crafting. You need to develop your skills with tried and true patterns and written as well as Video information available. Tandy has a full line of the old pattern and "How To" books by Al Stohlman as well as many others. If you don't have a Tandy close to you, they have a very good On-Line presence. Leather work is confounding and at the same time very satisfying. Learn the basics of carving and practice, practice, practice.
I am not going to go into what I think you are doing wrong at this time. Think about what I have said and don't take it as being too mean and critical. Not intended.
Ferg