There are two basic ways to hold a crochet hook:
1- THE UNDERHAND PENCIL GRIP:
Hold your hook with your thumb and index finger, and let the handle of the hook rest on top of your hand.
2- THE OVERHAND KNIFE GRIP:
Hold your hook with your thumb and middle finger, place your hand over the hook, and hold the handle against your palm with your remaining fingers.
Try both ways to see which way you feel more comfortable, and use the one that works best for you.
I feel comfortable alternating both ways to rest my hand, maybe you too! So always remember, there is no a better way.