I make it a point to always have paper with me though, in case I need to sketch out an especially good idea before I forget it. This is why you'll often see me with an open notebook at Scout events, in the bleachers at the ice rink, or even as I'm walking to pick up Trevor from school.
Here's an example of what my sketches often look like, scrawled on the back of binder paper:
This page is from last summer. I scrawled out the sketches and notes while waiting on a bench outside Trevor's robotics day camp. Some sketches are detailed, like the Kissing Hand Raccoon on the right side of the page, that I went on to create a few weeks later. You can spot the Cardboard Tube Shark on the left and the Cardboard Tube Bear in the middle. All three of those came out of the same brainstorming session.
Other sketches are pretty vague. There's a Pokeball at the top right, but no notes about materials. It just popped into my head as something popular that I should make. But I wasn't inspired, so it never made it off the page. In fact, I haven't made anything else from this sheet. That's not to say I never will. I'm still enamored with the idea of making myself into SuperCindy. Maybe someday. But in the meantime, hundreds of other ideas will have replaced it. Even as I'm typing this, I'm dreaming up a craft using a golf tee. Time to sketch it out!