Headband Curls! (one of the best No-Heat curl methods I have tried) -
This is a variation of the headband curl method by Oksana on The Long Hair Community. It's a no heat method to get beautiful spiral curls, while you sleep!
Go to this link ^ for Oksana's detailed picture tutorial.
All you need is a headband. I DIY'ed one from a pair of boxer briefs.
Measure around your head and make a mark.
Sew the 2 cut ends together.
Here are my results! Not bad for the 1st try. As with most no heat styling methods, it takes a few time to get it right. If you try it, don't give up if it's not perfect the 1st time! This should work for hair that is almost shoulder length or longer.