How can i thicken up my hair?

My hair is a very light blonde and its my natural color i have never died it. For cheerleading when we put our hair in ponytails i have to curl it to give it some body and it looks ok down? I heard of the Mane and Tail shampoo and i was wondering if it really does thicken up your hair? Or any other shampoos that can help with hairs thickness?? Thanks :)