Did you see the head band I posted in the General Knitting forum? Here is the pattern for that:
take you gauge for whatever yarn and needles you are using and CO enough stitches on a 16" circular to get to the closest multiple of 6 for 19". Did that make sense? For example, if your gauge is (let's make this easy) 5 stitches to an inch, you aim for around 18-19", so 19 x 5 = 95. Choose the multiple of 6 that is closest to this, like 96 sts or 90 (if going for 18").
Now work 6 rows of garter stitch.
Now work this diamond pattern over a 6-st repeat.
reading from right to left each row (because you're working in the round).
Now work 6 more rounds garter stitch and BO
Doesn't get much simpler than that. Takes less than a couple hours and only two colors, pattern easy to see and memorize.