Cast on 8.
Row 1:* K1, Pl* repeat to end
Row 2: *P1, K1* repeat to end
Continue alternating rows until your piece measures slightly smaller than the circumference of your head (you will want it to fit a bit snug because it will stretch quite a bit). Bind off. With yarn needle, sew end pieces together to form a circle.
Here's a picture of my friend, Emily, modeling the headband!