Food is an important part of Italian life. Italians usually take their time when eating lunch and dinner. Traditional Italian meals consist of many courses: first there's an antipasto (appetizers, or "before the meal"), then il primo (first dish), il secondo (second dish) with un contorno (a vegetable side dish), and then il dolce (the dessert). The antipasto usually consists of cold cuts and crostini or bruschetta, the primo consists of soup or a pasta or rice dish, the secondo consists of a meat or fish dish, the contorno consists of a vegetable dish or salad. Cheese and fruit may be served before or instead of dessert. Italians tend to eat lunch at around 1pm, and dinner is after 8pm. A full traditional meal is usually accompanied by a good glass of wine. In Italy, breakfast is not considered an important meal, and if anything, Italians usually just eat a few fette biscottate (a cross between a sweet cracker and toast) with jam, or a pastry (like a brioche, which is similar to a croissant) and a cappuccino. On that note, a cappuccino is never consumed after breakfast and definitely never after lunch or dinner. In the middle of the day, Italians drink caffè(espresso), usually standing at the coffee bar. You will never see Italians sipping a large disposable cup of caffè americano or eating while they are walking down the street. If people are in a rush, they will eat standing up.
Tips are merit-based in Italy, not standard like in the U.S. You are not obliged to tip, but remember, your server probably knows you're American and knows that you would tip in your own country. It never hurts to leave a few extra euro for good service.
If you order beef, it may come out fairly rare. If you ask for "well done", chances are that you will get meat far less than well done by American standards.
Realize that there is very little fried food in a Tuscan diet beyond coccoli (fried dough) and fried vegetables. If you see calamari on a menu without the word fritti, understand that it may come out sautéed or without any breading.
Butter & Bread
Butter is not normally served with Tuscan bread, which is salt free because presumably, salt would distract from the taste of the food the bread accompanies. Bread is usually eaten with cold cuts, the second course, or vegetables. Italians don't dip their bread in olive oil unless the oil is "new" or of particularly good quality, but they may fare la scarpetta (dip bread in the remaining sauce on their plate).