Find a wedding cake knife and serving set with crystal handles, and proudly display the set beside the cake stand. Buy a large package of stick-on crystals and carefully place a single crystal on a few of your personalized wedding napkins, and then arrange those napkins in a fun pattern around the cake table. Stick-on crystals are so cheap that it won’t matter that the napkins will later be thrown away.
Use caution about what your guests (especially younger children) might mistake for candy or frosting. Avoid placing anything not edible inside the actual cake batter or even on the outer layer of frosting that will not be removed before being sliced and passed out to your guests. If you do decide to decorate your cake with jewels, warn the cake cutter in advance that those items must be set aside as the cake is being cut. Or, ask your bakery about edible options in wedding cake jewelry design, and take your wedding bling to the extreme.