Thanks man. I'm far away from the top dogs. But I would recommend just keep drawing a lot and try different technics, poses, shading, coloring to learn a lot. I can also recommend this dude:
www.proko.com/how-to-draw-vide…Start from bottom of the page. He got tons of free videos that shows step by step how to draw the human body. He gives tons of tips on how to improve.
At the end of the day it's up to the artist on how much time u spend on learning/drawing. When you learn how to "remove" that feeling when you need to make something perfect, when that is removed you will be able to draw A LOT, and become way faster and better over time. Because you need to fail before you can succeed, and most of the times all drawings people make are failures/compromise that looks good in other people eyes because they cant see what the artist was aiming in the first place.
Hope that helped out.