How I made a Peerless watercolor palette.
I cut a piece of watercolor paper and folded it in half. I cut a piece of Yupo paper and used Washi tape to stick it in the fold. This yupo will serve as a mixing palette and keep the colors from blending across the page.
I used a circle punch to create the circles (but you could cut squares or small strips). I used a water brush beside each circle to demo what the color looks like.
For fun I painted balloons in rainbow colors (from the palette) on the front. Finally the palette slips into the pocket on my moleskine sketchbook, so all I need is a pen and a waterbrush and I'm ready to journal.