I've been to Italy many, many times. I'm often asked by those going about where to stay and what to eat while on the ground. I have lots of recommendations for those seeking such guidance, but I also thought it would be beneficial to share some (mostly food-related) tips on the more prosaic practices while in Italy. Here they are, in no particular order but starting with a tip about tips...
Don't Do It: Tipping is not customary in Italy as Italian restaurant workers are paid salaries or are part of the family/ownership. There's also a small cover charge per person added to the bill. If you feel compelled to leave a few Euros on the table as a gesture, fine: It will be appreciated, but don't make the mistake of thinking you are obliged to leave something anywhere close to customary US tip amounts.
Don't Stuff Yourself: Despite what many Americans believe, Italians do not eat four courses at every meal. You, therefore, should not feel compelled to take an antipasto, primi piatti, secondi, and dolci at every meal. My advice, to experience as many different dishes as possible, is to share plates by asking, for example, for one order of a plate from each primary course to be shared two (or even three) ways. This is better on the stomach and the wallet.
Be Italian at Breakfast: Yes, your hotel might have the customary spread to accommodate tourists but skip it for a caffe and cornetto (coffee and pastry) at the nearest bar (their "bar" is our version of a cafe). In a related manner, cappuccinos are not customary after morning among Italians, but you can have one later in the day if you want (just don't tell the Italians you heard this from me).
Eat & Drink Local: When in Rome...Exactly. Wherever you are, familiarize with the local cuisine (cucina tipica) and dive in. This goes for wine, too, and go with the house wine (vino della casa) whenever possible, though the region's most renowned wines are also recommended as well.
Avoid Lines: If there's a line around the block at some eatery, it's probably a tourist trap (hence the line). Look for places where the locals eat. Ask for advice or read blogs of reputable food/travel writers (Appetito has lots of such roundups from all around the country).
Eat Street Food: This is a great way to experience the local cuisine prepared simply.
Bring Comfy Shoes: There's no better way to kill time between meals than walking, but all that pavement pounding (especially on the cobblestones of Rome) can be hard on the dogs. Shoes made for walking (a lot) make for a much more enjoyable experience.
Take Note of How You Feel: One of the best lessons of Italy is that their food, locally sourced, carefully produced, and simply prepared not only tastes amazing but lends itself to easy digestion. This also goes for the wine, which lacks the sulfites required for importing to the US. So, yes, take note of the elevated flavors but also the effect upon your body and soul.
Take It Slow: It's easy to get overwhelmed by the abundance of beauty and offerings in Italy (happens to me every time), but to truly enjoy Italy you have to adopt their pacing, which is devoid of haste and overindulgence. Try to savor everything, knowing that you will be back and nothing will have changed.
Try to Speak Italian: One of my favorite things in Italy is how pretty much everyone you encounter in the morning will say, "Buongiorno." Return the greeting and use simple phrases throughout the day, like Ciao (chow) for "Hello," Grazie (graz-ee-eh) for "Thank you," and Prego (pray-go) for "You're welcome." Learn a few more simple words/phrases to immerse a little more and add to your experience.
Buon Viaggio!