Wearing high heels doesn't have to mean punishment for your feet. A few foot exercises and strategic posture could make standing for a long time in heels (like at a Christmas party) less painful than usual.
The key, according to Vogue and foot yoga teacher (yes, you read that right), is to build up the outer part of your feet -- the side opposite your big toe -- because this will lift your arch and strengthen your foot overall. Strengthen your feet (sans heels) by balancing your weight on different parts of your feet.
Then, the next time you're going to be out for a while wearing heels, remember to shift your weight to your now-strengthened outside edges of your feet for a less painful experience.