We have some birch trees just down the walk that have very peel-y bark. The other day I broke some of the peels off and brought them home to use as collage material. I soaked the bark in very dilute matte medium in hopes of sealing it so it won't deteriorate quickly, then I glued it to a half-sheet of paper onto which I'd spread some gesso and then a dilute wash of acrylic paint. I put the gesso on so it might suggest birch trees and I used colored pencils to bring those shapes up a bit. I also, obviously, stuck on a piece of paper which I'd painted for collage. I don't know whether it's finished or not and if not, where to go next. Suggestions?