Consider carrying a clutch. You may have a few items that you want to carry with you, like your cell phone or compact. The best way to go about bringing these things is to find an elegant clutch purse that works with the color and style of your dress.
If you don't want to carry a clutch, though, you might be able to persuade your date to carry your phone and extra supplies in his pockets. Just make sure that this is okay with him before you take that option.