There are plenty of books and tutorials out there that describe how to draw things well. We spent a lot of time in school learning how to draw things beautifully, in all sorts of photorealistic ways. This is considered a hard skill and in many cases a cost of entry for being a commercial artist.
So please excuse the rudimentary nature of this post. I suck at drawing with a pencil. But that has never gotten in the way of putting out solid design work and sketching ideas for buy-in by my peers.