What products or shampoo will help my hair stayed curled when i curl it with a curling iron?

My hair is pretty straight. So when i curl it it normally falls flat within an hour or so. What can i use to make sure it stays? Which products?What products or shampoo will help my hair stayed curled when i curl it with a curling iron?
Me and my sister use this brand called Shique and i think it works really well. My sisters hair curls right when she gets out of the shower when she uses it! Hope this helps! :D