I used to put sketches in these publisher dummy things, hardback books with nothing printed on the pages. They are great, I still use them, but prefer doing sketches on watercolour paper and painting them up with watercolour paints, simply because it's a great way to keep the lines.
This sketch I eventually used for my painting Mermaid, in which I added some text from songwriter/artist Tori Amos.
Ha. I still prefer the drawing! But the painting is very large, about 1 metre long. And it was fun to make.
Just 100 unique visitors to go to read 10,000. And greetings to my most recent viewer from Brazil!