Traditionally, after your officiant pronounces you wed, you and your wedding party will recede down the aisle in a custom unsurprisingly called the recessional. Just like the processional—you and your wedding party's entrance into the ceremony—there's a very specific order to things. In case you're in the dark, here's a guide to how you, your newly-minted spouse, your bridesmaids, groomsmen, and parents should leave the ceremony.
The recessional begins immediately after the first kiss you have as newlyweds so it shouldn't come as a shock that you and your partner will lead the way back down the aisle. Not before your maid-of-honor hands you back your bouquets and straightens out your gown and its train if it should need it. After you come the flower girl and ring bearer, followed by the maid of honor and best man.
The rest of the recessional will depend on who makes up your wedding party. Bridesmaids and groomsmen can walk back down the aisle in pairs, which is best if you have an even numbered wedding party, or they can go solo, which, you guessed it, works well when you have an uneven number of bridesmaids and groomsmen. After that your parents may want to follow, but it's not a must. This won't come as a shock when the time comes because you'll make sure the order is planned during your rehearsal the day before.
P.S. Every good photographer should know this, but they should be waiting at the aisle, ready to capture your triumphant smiles.