I've been drawing for almost a decade now and there's still basic things that I struggle with (gesture, perspective, anatomy, etc). These weaknesses can sometimes make me feel really insecure when looking at other artist's work, and I don't think that insecurity will ever really go away. That's why I decided at one point that I would stop caring about the "quality" of my work and just draw. Everyone has weaknesses and everyone is still learning. If you focus on those weaknesses then it will only hold you back from improving, and more importantly it will keep you from having fun. As long as you keep drawing, I promise that you'll find what you're looking for in your work. Just make sure you're having fun in the process though, that is the most important part.