Pin curl your hair as if it was in a roller every night before bed. Meaning roll sections (same sections that you had the roller in) of hair on your fingers and than using a bobbypin, pin the curl to your head. When done, you should have a head full of invisible rollers. Don't worry about sleeping on them, since they won't be 'crunchy' you don't have to worry about spoiling them. Your curls will last for days like this.
**Alternate method**
Think of a slinky, think of the slinky in it's regular position just resting on the floor. Now, after you imagine roll sections of your hair with your fingers, using a bobbypin, pin your hair to your head so that the "O" - think slinky- is flat against your scalp.