I had what I consider an unsuccessful painting with a large central image. I painted over it with light coral and scraped the surface to let the texture show through. After coating it with glossy gel, I used matte medium to remove the shine, and put collage pieces onto the surface.
Now it looks like this. I have covered up a lot of the collage pieces with light greenish white, and once it dries, I will sand the surface to expose some of the underlying colors and shapes.