There is a wonderful blog tutorial by a very crafty woman in Mexico on the subject:
http://blogdelanine.blogspot.com/search/label/handcarvedstampstutorial
People doing this are also doing these things:
Entries
... and a mushroom (fly agaric) and grass next.
As one (at least I) cannot work very accurately, the results have a style of their own, which I like!
