This will fit infants through school-aged children. I can stretch mine to fit me but it's a tight fit and my yarn is strechier than normal cotton yarn.
A small amount of cotton yarn (I used Nashua's Cilantro cotton blend yarn, this yarn is super stretchy and has great stitch definition)
Optional: yarn of choice for flower decoration
fdc - foundation double crochet
sl st- slip stitch
dc- double crochet
shell stitch - 5 dc in the same stitch
foundation double crochet (fdc) - this is a chainless foundation stitch which makes for a much stretchier finished item which is ideal for headbands. I can't explain it very well but Teri over at Diamond Crochet & Crafts did a great tutorial which you can find here http://diamondcrochetcrafts.blogspot.com/2011/12/how-to-do-foundation-double-crochet.html
Row 1: Do 30 fdc stitches (count the beginning ch 3 as one of the stitches). Turn. (there is no turning chain)
Row 2: Skip 2 st, *shell stitch in next st, skip st, sl st in next, skip st*, repeat from * to * to the end of the row.
Turn your work 1/4 turn so that the end is facing up. Sl st in in side of the beginning ch 3 of the foundation row.
Row 3: repeat row 2 stitching into bottom of the foundation row.
At the end of row 3 do not finish off, instead fold right sides together and slip stitch the two ends together.
Finish off and weave in ends.
Use as is or add your choice of decoration. I added a nice and easy flower from one of my favorite blogs. You can find it here http://neannersshop.blogspot.com/2010/11/super-duper-easy-perfect-posy.html. You can glue the flower to an aligator clip and switch out decorations to match outfits.