Before putting anything on it score the ham with a cross hatch pattern so that whatever you put on it gets down inside the ham and doesn't just sit on top of the fat cap. Ham takes a long time to get to temp in the center so go ahead and sit the ham on the counter (out of packaging, but in the pan) so it can get to room temp. Ham can be served at room temp since you already buy it fully cook and what I do is make a thick glaze and then throw it in a 500 degree oven for 15 minutes to let the glaze crack and get crusty. I make the glaze with brown sugar, a little orange juice, cinnamon, cloves and anything else that sounds yummy. Reduce over the heat in a small sauce pan then drizzle over the top.
If you are bound and determined to serve a warm ham then start with the ham covered so you don't lose the juicy interior with a can of doctor pepper in the bottom, then kick it up at the end uncovered with the glaze.
