For building moe appeal, you can't go wrong with cooking. Making lunches and such. Try to get a little closer physically. For example, if you walk together grab his arm and smile, using the pretext of staying warm. Play footsie now and then. Wear above-the-knee socks with skirts short enough to leave one or two inches of bare thigh. Let your hair grow long and try a variety of styles like twintails or ponytails. If he has old shirts or t-shirts, ask if you can have them to use as a nightshirt. If he asks why, say it's because the scent reminds you of him.