I sat in front of my bird's cage for about two minutes with a big lettuce leaf and nibbled on it noisily. I even made "mmmm" sounds like you would with a baby. He stared transfixed and seemed to figure out it was food and naturally, being a baby, he wanted it.
As soon as I clipped it to the side of his cage, he went for it. I haven't tried anything else yet, but God forbid he doesn't get his lettuce leaf PRONTO in the mornings.