Communicate openly with both sides of the family early in the process to discuss which traditions they would like to incorporate.
Make it clear that this is your wedding, yet you also want to make your families' customs a part of your day. If they're not 100% happy with your choices, don't sweat it. The important thing is you tried, and they'll probably come around once they see the awesome party you've put together.
Pick a ceremony site that will accommodate your wedding, and know their rules. If you want to get married in a religious center like a church or synagogue, you may need to take classes or follow special guidelines before you can marry there.
Consider getting pre-marital counseling. It may be the differences that first attracted you to each other, but for a multicultural marriage to stand the test of time important topics like faith, finances, and childrearing should be discussed in detail before you walk down the aisle. Talking over the big stuff with counselors like Drs. Michelle and Patrick Gannon of Marriage Prep 101 can clarify expectations and help you avoid trouble down the line.
Educate each of your families on what would be considered inappropriate behavior in the other's social world. A wedding is not the place for cultural faux pas.
Don't feel you have to put all your cultural eggs in one basket. If your backgrounds present too sharp a contrast to be equally represented during the ceremony, there are other opportunities to give each family its due. For example, reserve the ceremony for the bride's heritage and turn the rehearsal dinner into a celebration of the groom's. It's the perfect occasion to explore the African custom of "Tasting the Spices," or introduce guests to o-shaku, the Japanese sake pouring ritual that reaffirms the bond between friends. If you or your groom is South Asian, why not host a mehndi party for your bachelorette gathering? All the female relatives will enjoy expressing their inner artist through decorative henna designs.
Personalize your ceremony. Some officiants of differing religions are open to conducting the ceremony jointly and can help you design one that honors both ethnic and religious traditions. Just make sure the ceremony doesn't try to incorporate too much and run too long.
Help your guests understand any special wedding rituals. If you're including unusual elements in your wedding, such as the Hispanic custom of wrapping the couple in a lasso, provide brief explanations of their significance in your wedding program so that your guests can appreciate their symbolism. Alternatively, your officiant can clue everyone in.
Take advantage of ethnic traditions that do double-duty. Did you know that the breaking of a wine glass after the "I dos" is not only a Jewish custom, but an Italian one as well? And the canopy covering an Indian ceremony, called a mandap, looks just like a souped-up Jewish chuppa!
Get inventive with the food. Fusion cuisine is super popular nowadays, so make a cutting-edge gourmet statement while demonstrating how well two cultures can blend together.
Schedule dance classes for family members before the big day. Not only is this a fun ice-breaker, but teaching both sides of the family a few key steps of the hora or some salsa moves (or whatever specialty dancing you'll have at your wedding) will make them more likely to enjoy participating.
Honoring your families' cultures is great, but don't forget to showcase your own personalities. Put your favorite songs on the play list and teach Cousin Habib and Tia Elena how to rock the house. Or personalize the wedding favors—chocolates from Ghirardelli Square where you had your first date, for example.