Keep a spot on your whiteboard open

I have a couple of whiteboards in my office. Sometimes they are full and sometimes you can find space. I've noticed a trend. When there's open space on the whiteboard people draw when they are explaining an issue, feature, or some other aspect of the system. If the board is full, they don't. I learn best visually, so I've developed the practice of making sure my board is clear. It also means I get really cool diagrams on my board for a period of time after the discussion. That helps the ideas soak in.