Several things can sabotage your shiny hair. One of those things is styling your hair while it's still wet.
How do you know if your hair is too wet?
Do you hear a hissing sound and steam coming off your hair while styling? That is never a good sign.
The problem
Water boils at 100 degrees, your straightener gets much hotter than that. The sound you hear is the sound of water bubbling and expanding in your hair.
The solution Preferably style your hair when it is dry and use a product that protects your hair from the heat. Do you really suffer from lack of time? Then use a straightener that is specially designed for wet hair.