Tiramisu
As you eat, feel free to drink your wine, but beware that once your glass reaches the halfway point, someone is sure to top it off. If you don't want any more wine, leave your glass relatively full. However, not touching your wine at all is very rude, so drink enough that your glass it topped off at least once. Ironically, although not drinking is rude, over-drinking is also so make sure you know when to stop.
As you finish your first plate, don't take more food, rather compliment the host, who is surely eager to offer you more. After you finish your second, third, or even fourth helping, the meal should finally come to a close. Your host will again be sure to offer you more food and it will take some persistence before he or she finally leaves you alone and accepts the fact that you are finished eating.
If you're at a restaurant, or even in an Italian's home, place your fork and knife together at the angle of 5:00 on a clock. This will let the server know that you are finished eating. Even if you're finished though, wait until everyone is done before getting up; dining in Italy is a social event and it is expected that you leave with those you came with and they are probably in no hurry to leave. This relaxed attitude makes getting the bill at the end of the meal a challenge; it will not be given to you until you ask for it, no matter how long you remain seated. If you invited your guests, be prepared to pay for everyone's meals, whereas if you are the invited guest, offer to pay, but expect to be turned down. Accept their gift and thank them for the meal.
Typically when you eat at a sit down restaurant with a waiter or waitress, a service charge is included, but if not, you should tip about 10% of the bill. Sometimes, a fee for dining at a table will also be added to your bill; this is often charged for every person at the table; to avoid this charge eat or drink at the counter as the locals do. In bars a tip of whatever loose change you have is appropriate.
Drinks
Every popular international beverage is available in Italy, including tea, juices, soft drinks, and milk. However, coffee and variations of coffee, such as latte, cappuccino, and espresso are among the people's favorites.
For alcoholic drinks, wine rules in Italy, and with their quality control measures in place, it's tough to find a poorly made wine. Plus with enough variety, a bit of searching will guarantee you find one that suits your tastes; among the most common varietals grown and produced include sangiovese, nebbiolo, and barbera for reds and pinot grigio is among the most popular white wines. Beer and liquors are also consumed, but aren't nearly as popular as wine, although all popular international brands are widely available.
Generally speaking, the tap water is safe to drink in Italy, but check with locals for any particular regional differences. Also, many people may have troubles adjusting to the local tap water, as it will most certainly be different from what your system is used to.