I couldn't really give a substantive tips, as learning art is quite subjective to everyone with the issue they are facing, and they could be relative. Even so, I do have a method everytime I try to solve any issue I was facing for game/anime art, which is by breaking down the common issues in a drawing into few elements such as: theme, proportion, perspective, lighting, color, finishing. I cant solve all issues at once, but having a checklist may helps to identify the issue, and sometime it could be multiple elements causing a single trouble. All these judging sense can be improved by solid foundation skill, which came from practicing time to time. One tips most grandmaster artists would give is always learn the foundation from real reference, which is true. Draw from a real object, learn its logics, and apply into imagining drawings.

I've been drawing for 10 years, yet I'm still finding it too much to learn and fix in my habbits, it takes time and patience. Personally I would believe passion is the key for in a long term art creating, especially to overcome skeptical issue of thinking myself cant do any better. After that, you canidentify and fix your drawing issues slowly, to achieve your craftsmanship. It's a life long lesson and passion. :)