General rules for using rollers:
Choose the size of roller by the length of hair you have and the tightness of curl you want. Hair must go around the roller one-and-a-half times to give lift and volume as well as to stop the roller from falling out. For every turn around the roller after that, you will get more and more curl and a tighter result.
A section (piece of hair you are putting the roller into), should be the same size as the roller or larger.
Direct the section of hair to be rolled in the direction which you finally want it to go in the style you are aiming for. For example, back at the sides or rolling away from the face.
Offset the sections or "brickwork" them for a more natural modern look. If you don't offset them placing each roller directly behind the previous one will leave "tramlines" that will show in the finished result.
Make sure the hair is totally dry before you remove the rollers as the hairstyle will not last if it is still damp.