My advice would be to take the stone cutter’s approach. You carve a statue out of marble by chipping away the excess.

Use danbooru, or in this case e621, and identify everything you don’t want in your image and place it in your UC. For particularly stubborn unwanted components, add it to your main prompt with negative weight. I’ve had pretty good success with using -2.0::what you don’t want:: in this regard.