Here are a few 2 minute costume sketches I did in life drawing class for Introduction to Concept Art this year. 

Great class! Really cemented my commitment to continue field sketching and life drawing. 

 Life drawing is like meditation; you can't go into it thinking too much about the outcome, it's about the state of mind.

 You have to do it for you (to become a better artist) not for the drawing.

And you have to have a completely different attitude to paper.

Because a lot of what you will do is a complete waste of space, at least, for a while

I am trying to stay in the habit of field sketching and life drawing. It should be a way of life for artists. Heck, people. It's good for your brain!