Developing the ability to be able to simply obverse and draw that which is in front of you with a degree of accuracy not in terms of photorealism (which is a bit of a blind alley), but in conveying the weight and structure of objects, as well as their spatial relationship to the world around them is invaluable if you want to be able confidently draw from your imagination. Have a look at these Giacommeti sketches: -
Very simple, but you get a sense of a solidity to the objects (particularly in sketch 2) despite the fact that in reality it's just lines of a piece of paper, they convey a sense of the space.
Just get to grips with the basics and then evolve your own style from there. If you attempt to ape others without getting the basics down your work will just come across as derivative rather than innovative.