First of all, congratulations! I can't think of a more romantic place to say "I do." Regarding sightseeing, I'm picturing an equally romantic combination of casual skirts and feminine tops, paired with comfortable shoes and a small crossbody bag. Bring a lightweight cardigan that you can toss over your shoulders when you're in a museum or touring a cathedral. I was in Old Navy the other day and saw lots of stylish items under $30 that will work well for your trip, and I've included some of them in the outfit ideas below. Click on any item for shopping details. Buon viaggio!
Outfit idea #1: Italians have a reputation for being stylish but you'll see a wide range of fashion tastes represented on the streets of Rome. Blend in by wearing this white ruffle top and blush skirt - both are supremely comfortable yet pretty.