I've only ever been to Sardinia, but the biggest thing about that trip was how fantastic the food was.

Eat pasta a lot, because it will be fresh and better than anything you have had in the U.S. Go to the grocery store and buy yogurt and cherry tomatoes: the yogurt will be creamy and not sour and the tomatoes will sweet. Even if you don't like seafood, consider trying something if you are in a coastal town. Don't be deterred by the outside appearance of an establishment--some really crappy looking places ended up having excellent food.

And the time of year you are going, it will be *hot*.