Time limits seem to have an effect on my sketching, a positive one. Maybe it's not having time to think that forces me to put down on paper exactly what I'm seeing. I wish I could do this more often without needing to have a clock ticking. Maybe I should start wearing a watch. Below is a drawing of a sleeping child, I knew I had moments before he woke up.
Image: Sleeping Child (www.tracybutler.co.uk)