felt bird pondering flight (bird mail)
palette people (seen in an image of dried paint)
cactus on the radio
With a travel set of Windsor-Newton paints I use a better-quality travel brush with a pointier tip rather than the one in the set. The pointy tip, like a sharp blade, gives you more control and a better result. Clean water helps, too.
I sketch out the subject first, then paint it in, usually light to dark. Because the cards are sized, the paint only goes where the water is. Let an area dry before painting immediately adjacent to it unless you want the colors to blend. The faux stamps are punched from random papers and pasted down with PVA. Yes, they warp a little. But that's okay. They're also going through the mail.