Well, just to give you a basic idea, you'd start with a round (ch 4, slip knot through the first ch), then increase it to the size of the head. To do this:
8 dc through the center ring, slip knot through the first ch, then ch 1. (use some sort of marker ring or safety pin to mark the beginning chain).
2 dc in each loop from the previous row, sk through first knot, ch 1.
(1 dc in first loop, 2 dc in the next) repeat back to the beginning, sk, ch 1.
(1 dc in first and second loops, 2 dc in the next,) repeat back to beginning, sk, ch 1.
(1 dc in the first, second, third loops, 2 dc in the next), repeat to beginning, sk, ch 1.
continue this increase until the hat is big enough for the head, then hold that pattern until the beanie is a long as you'd like. you might want to finish it off with a few rows of sc to give it like a tighter brim that'll help keep it in place. i'm no expert, but i like working in rouds - hope this helps! (I also hope this makes sense, as my daughter has me reading Beauty and the Beast to her right now as I'm typing lol)
be well - Lee @ Lee's Teas