There's a great post on LoaA today on architectural sketches. I totally agree with Bob, and I think this particular type of communication is starting to fade away as computers are taking over. It seems to me though that sketches can convey ideas so quickly that people forget how awesome the process really is. I think people think they have to draw on the computer. Not so!
There are some people that I watch while they sketch and it feels like hearing nails on a chalkboard. It sounds horrible but you know what I mean. We call it chicken scratch for a reason. If that's how you feel about your sketching, there's an easy fix: just do it more. Get yourself a sketchbook and a nice pen. Get into the ritual of it, but don't pressure yourself. It's more about working things out than about creating art. It's about the process, not the final product. There's something very therapeutic about it. I guess that's why I'm always so entranced watching Buddist monks do Zen calligraphy. It soothes the soul and gets you closer to Zen.