This is one of the quickest hats I have ever made. It is crochet. I think she looks so cute but then I biased.
Wool: what ever left over yarn you have
It really takes about an hour to make, I have made about 4-5 already (many different colors), pictures soon.
For sizing I just use bigger or smaller crochet hooks. The flower on this one was a little big, so I have now made smaller flowers. Have a great day.