From all the plenitude of art and nature journaling websites, I'm following John Muir Laws, painter of birds and trees and bugs, this summer. Late last night I played with a "How to Paint Mushrooms to Look Wet and Glossy" blog post. I copied his drawing freehand, using a Micron 02 pen and then took Caran d' Ache Supracolor Soft II watercolor pencils with a water brush to add the color.
I let the drawing dry overnight and added the opaque accents that show reflected light for the glossiness. The opaque white is watercolor, too. I used Winsor and Newton Designer Gouache "Zinc White" and then added touches of Uniball white gel pen.
It's my first time trying this technique, but once you've done something with your hands, your brain starts firing in a new way and you just might remember the technique when you need it again.
Here's a link to the Laws website. If you are a bird watcher, you might know his work well already. The lesson using mushrooms is on his blog.