'Accidentally' touch his hand

When you're standing or sitting next to him, pretend to accidentally brush his hand as you, say, reach to put your hair up. Pretend that you didn't notice, and your crush will probably stare at you questionally. After about 1/2 of a second, pretend to "just notice" him looking at you out of the corner of your eye, turn to him, smile at him, and turn back to whatever you were doing. He'll probably still be wondering about you, and you'll come off as innocent, cute, comfortable, and friendly.