What new shampoo can I use?

Whenever I wash my hair, it stays very flat and VERY unmanageable. I always tease my hair, but whenever I tease it, it falls totally flat! Its like I have to wait for my hair to get dirty when I want to style it :( . is their any other shampoo's that can help? i have tried lots of diffrent ones haha..or, is their any way I can make my hair manageable after I wash it? thanks :)