Understand Anatomy
Understanding anatomy helps me draw characters well and more efficiently, but in an abstract way it helped me learn to draw other things as well. I learned to draw anatomy by breaking the human body down into simple shapes. When you are doing that with something as complex as a body, doing it for something like a vehicle, mailbox, furniture, etc. becomes a cakewalk!

When I was coming up and learning anatomy the internet didn't exist. Now there is an unlimited anatomical book in google, dive in! I'm going to join you, there is always something new to learn!