Consider buying two pairs of shoes, one with a lower heel, so you can do a changeover when it's time to hit the dance floor - even an inexpensive pair of satin slippers or jeweled flip-flops could do the trick. You absolutely want to avoid killer foot pain.
If you're on a tight budget, no one is going to notice if you bypass the Christian Louboutins under your long gown and wear basic satin sling-backs, which you can buy for about fifty dollars.
If your feet are prone to swelling, buy your shoes a half size larger than usual, and bring along pads, just in case.
If the shoes have a smooth sole, scuff it up for traction: Take a pocketknbife and make a series of shallow crisscross cuts on the soles.
Put in extra pads wherever they'll help. In sandals, place them under the ball of the foot. In pumps, you may also need pads under or behind the heel.
Walk around in your shoes at home for two to three weeks before the wedding to break them in. If you're taking dance lessons, wear your shoes so you'll be comfortable in them on the dance floor.
Look for a style you can wear again, especially if you're spending a lot. If you're going with ivory satin shoes, you can dye them back after the wedding.
If you're not a habitual heel-wearer, you might be better off opting for platforms.