Hair question!??!?!?!?

Alright I have very very thick hair and it's pretty long a bit above the middle of my back and I really want to curl it but no matter what I do the curls will stay for like five minutes and then fall and my hair then looks like crap I did all the tricks I've seen online to try and make it stay but they don't work am I just destined to never have curly hair?!?!? Good tips please!!!!!!