Depends on what you are doing. If it's just a casual date then just dress up slightly more than usual. If you are not a skirt/dress person, he may notice you trying extra hard if you wear one. If you are going to a nice restaurant then you can dress up even more! Heels paired with pants or a skirt kicks them up a notch, maybe a somewhat low cut shirt to show off the girls a bit and a jacket. Or a knee length, v-neck dress with a jacket and some heels.