I have no advice for clay, but are you set on doing that kind of ornament?
Last year I did hand print/foot print reindeer ornaments. I used sheets of craft foam, and made the head (footprint) dark brown and the antlers (hand prints) light brown. I didn't take a picture of mine, but they were something like this:
This year we're going to try and do the snowman hand print ornaments, like these:
Just some other ideas, in case you were getting frustrated with the clay. I'm hoping to keep doing some kind of hand print or footprint things with DD until she's too big for it. Good luck!