A few weeks ago I wanted to knit a maple leaf. I had just one ball of Boku(silk wool blend, 99 yds), and it ended up about 15" diameter.
When I went about knitting the leaf I made the leaf from memory. I've known the bigleaf maple all my life, so I'm pretty familiar with it(palmate, floppy, pointy...), so part of the fun was NOT looking at a leaf for reference until I was done, seeing how well my memory served. So I started with palmate, ok, 5 sections, then worked on the center three sections, then the center 1. Hm...5, 3, 1, those numbers are familiar! They are Fibonacci numbers(fascinating things everyone should know about, google is your friend). One problem was how long to make each section so it would come out proportionate. When I recognized the Fibonacci connection, I just used the numbers in the rows and point BO's and the proportion came out just right. I did have to not knit the "fingers" of the leaf as long as I would have liked because I just had so much yarn, but no big deal.
The stem was last, a simple i-cord with a flare at the end for where the leaf attaches to the tree. Then I neatened up the outside edge with crocheted crab stitch(which also gave me a nice places to hide the ends so it is reversible). Doing this gave me lots of fun ideas for the leaf form.