How do u make your hair.......?

poofy? how?! i think it looks relly cute! and i have a nother quiston how do u make your hair wavy?how do u! it will be sooooooo cool if i can make my hair wavy and poofy! i tryed shampoo afther shampoo! never worked! I want my hair wavy or/and poofy on the first day of school!i need help!A.S.A.P!!!!!!! and by the way my hair is straite.(st-r-ate)