How to keep curls in really straight hair?

I have really straight %26amp; thin hair, so every time I curl it, the curls fall out within a couple of hours..

What is the best way to keep the curls in (Hopefully without a ton of hairspray)

How to keep curls in really straight hair?

For every single section of hair, she sprayed a ton of super heavy duty hair spray on it. Both top and bottom, roots to ends. Then rolled it with either the curling iron or hot roller. The trick is to make sure the thing is really really really hot, and the hair spray is still sorta wet on your hair. She'd take the curling iron or roller out but keep the curl rolled up and pin it in place. Do that all over and then at the very last second, on your way out the door, take the pins out and shake your head to loosen the curls. Don't comb through or anything. And probably one more shot of hairspray all over to hold.