I have naturally curly hair, and occasionally I love to scrunch it and go for voluminous curls, But my hair is also frizzy, so I have to be careful - otherwise I look a bit like a frizzy poodle type thing.
I love trying out new curl definer products. There was one I tried years ago that I loved, But it was discontinued and I've been looking for something as good for ages. This is that product.
The Clynol Texture Swirl Curl Definer is a cream that you put through your towel dried hair, and then you can blowdry it in (this product also protects from the heat) or you can leave it to dry naturally. I choose to let my hair air dry, because heat is bad, especially in frizzy/curly hair.
My hair dries into perfect curly ringlets with this product - I love it! I just make sure to keep scrunching my curls a bit as my hair dries, and voila!
I'm not sure if this would help to curl non curly hair or not, or whether it is just designed to enhance natural curls .. But if you are looking for a good hair curling styling product, I would recommend this.