How to tie a bandana
1) Grab your bandana and fold it in half diagonally. Drape the resulting triangle around your neck, with the center point down your back.
2) Bring the two corners together a couple of inches back from your hairline and tie in a single overhand knot. Make sure the tops of your ears are covered, and make it snug - you don't want your bandana sliding up the back or the front of your head.
3) Hang on to the knot with one hand so it doesn't come undone, and with the other hand grab the center point and pull it up over the back of your head so the point comes just past the knot. Be careful, sometime the fabric folds in on itself or grabs itself and if you pull too hard too fast it'll just pull the whole thing up the back of your head. Lay the point you just pulled up over the center of the knot. This is where three hands come in handy, but you can do it. Use a couple of fingers to hold the point down, and tie the knot again (make sure it's a square knot, and not a granny!), catching the point in the knot.
4) If you think your bandana might slide up the back, use a couple of clips or bobby pins to secure it to your hair.
5) If the knot has a tendency to slide backwards, consider snagging some of your hair in the knot (just be careful when you take it out). Or if you'd prefer, use a couple of pins, just try to make sure they don't show.