While this is a fun way to get kids involved in stamping, there really is a right way to do it in order to get a balanced, well-designed page. Star with the largest stamp you plan to use. Stamp them in triangles around the page. Look at the first picture. Notice how the maple leaves in the top right quadrant form a triangle? The bottom three form another triangle, but they aren't exactly the same. If you stamp them all just alike (with equa-distance and similar angles between them) you'll end up with a page that is TOO designed. It will look too patterned and not random enough. Make sure to stamp right off the edge of the paper as well (have scratch paper underneath) to give your paper a look of continuity.
Once you add your large items, fill in with smaller images and tighter triangles. Be sure to rotate your stamp when you make the impressions so they don't all look alike. If you don't have markedly large stamps, you can still get a great look with the smaller stamps. You can stop at this point, and have a loosely stamped page. Just make sure you have enough of the paper stamped so that every small section you will cut (not less than 1x1 inches) has at least part of 1 or 2 images. If you have too much blank space on the paper, it will not work for this project.
In my opinion, the more the merrier! I love the way the paper looks when I fill it entirely with different images. The less white paper that shows through, the better I like it. It also means I don't have to worry about how or where I cut my paper since all of it is designed.
Once I decorate my paper, I cut it along with 2 coordinating cardstocks to design the cards. I used the CTMH Originals Card Confidence program to design the cards and I change them everytime I make them. Often by the time I get to the 9th or 10th card, I have to get a little creative and adapt the design I want to whatever paper I have left. All of the blank places that you see on these cards were filled with sentiment stamps or artwork (mostly sentiments). I also added brads, ribbon, and some "Just Blooms" leaves to the final cards. Usually I use Cranberry, Autumn Terra Cotta, Garden Green, and Desert Sand with my Autumn cards, but I thought it might be fun to try them with some non-traditional colors. I like the way they turned out, but I do prefer the richer colors that I normally use.