At the beginning of each round, or row, you can do which ever dc start you like, but I personally like the dc shown here, or here. There are two sized here, both tested: adult regular, and (adult large).

I crochet particularly loosely, so I typically use a pretty small hook for worsted (3.5mm)--but I highly recommend at least 4.5mm or 5.0mm for adult regular.

CORRECTIONS TO PATTERN:
Begin ear flaps and back:
1. 39 (47) sc into front loop, just like for the front flap, turn 2-4. 14 (15) dc, 1 hdc, 9 (15) sc, 1 hdc, 14 (15) dc, turn

Contrast color:
Begin earflaps:
1. 39 (47) sc into front loop, just like for the front flap, turn 2-4. 14 (15) dc, 1 hdc, 9 (15) sc, 1 hdc, 14 (15) dc, turn

ADDED 21 DEC 2015:
Gauge is 13 sts across 4 inches, 7-8 rows across 4 inches. This has been tested on the adult large hat. This fits a person with a head circumference of 22 inches (the hat fully over the forehead and ears). As soon as I test the adult regular size, I will post the head circ it should fit.