How do I keep my hair straight?!?

My hair is naturally very curly. I own a chi straightener which supposedly works very well. I have tried so many ways to keep my hair straight like putting pantene stuff in my hair while its wet that makes the straightening easier. I have tried hairspray. Everything I try my hair doesn't stay straight. It really bothers me. I take my time to get every kink out and flips and poofs out. Any suggestions like products or things I should do to my hair before straightening or after to keep it from curling/poofing up?