I called my uncle today and we ended up talking a little about sketching. He has a background in animation and used to work for Disney. He gave me some interesting tips that animators use which translate well to product sketching.
Draw the subject from every angle in 15 degree increments. I shortened the amount of views here because it takes forever and is quite difficult... So if you think you know how to draw something, draw it from a completely odd angle.
Draw the subject and flip it (on a light table or digitally) to see what is incorrect. I learned this in studio but I'll be doing it more often.
I discovered that the perspective was a bit more dramatic than what I intended.
My uncle also plays the theremin which is cool.