Here are what I've done.
1. I've selected a few pattern papers that I want to used for my background.
2. Then I've cut out some chunks of leaves designs at the side of those strips of pattern papers before pasting it down on my white card stock. Later, I've cut out some self made leaves masks to do some masking on parts of the white card stock too.
3. Lastly, I've also add those masks as part of the background.
This technique had created some unique depths on the background paper.