Take the top layer of your hair in the back and hold it straight up so it's sticking up. Take a ratting comb and use fast short strokes towards your scalp at the base of your hairline that is not visible to you. Then smooth out the hair over it when you drop it back down.
Hold whatever you'd like to tease at the ends and hold it straight up. comb/brush the first....lets say 3 inches of your roots and brush towards your scalp, making it ratty. don't tease it too much, unless you're going for the 80's look.