Once you understand the principal/anatomy of a hat,you can use any yarn or stitch pattern.
Read Cornel’s anatomy of the hat here http://www.ravelry.com/patterns/library/happy-holiday-hat
or see my pin.
1) Crown: is a flat circle,starting with 12 sts. For a slightly rounder snugger fit and usually with thicker yarn,I start with 10 sts.The circumference of the flat circle determines the width of the hat.Average is about 17 cm.
2) Side: is a straight tube which ends at about the tip of the ear.
3) Brim:Can be a continuation of the flat circle.More incr give a floppier effect.I have yet to find the perfect pattern/yarn combo.Thicker yarn(Aran wool) and a smaller hook, Elza’s method of crocheting over the previous row, and narrower rather than wide seem to work for a stiffer brim.
Enjoy and show!