Drawing for Designers

For my birthday last week, my friend Rachel sent me a book, Drawing for Designers by Alan Pipes. I'm starting to further understand my design capabilities and with it comes an increasing need to be able to sketch out my ideas to help convey them to my professors, teammates and others who play a role in the design process.
What the book has shown me is that there is a complete range of drawings. Its ok for things to be messy as long as I am getting ideas onto paper and out of my head. There is a time for in depth technical prints or 3D renderings, but there are also a place for quick 4 line sketches that show a shape or general idea. Sketching is something that takes practice and I'm certainly up for the challenge.