I like written patterns for many things but after I have worked them many times I can normally do them from memory without the pattern. I have been working on a few things this last month for daughter #3 who has a birthday this coming Friday. One was from a pattern I found here:
The second was totally from my own creation. I simply used half double crocheted stitches row after row until I was satisfied with the color combination.
Sometimes I just play with the yarn that is currently on the hook and come up with something undexpected. I made the little bunny ears for the sweetie of the house when I made the kids Easter bunnies.