Italy's food is regional in a way that most countries' is not. What you eat in Bologna is not what you eat in Naples or Palermo, and an Italian will tell you — firmly — that this matters. The genius of Italian cooking is not variety for variety's sake but precision: a few ingredients, treated correctly, at the right time of year.
The basics. Coffee in Italy means espresso, short and strong. A cappuccino is a breakfast drink; ordering one after lunch will earn you a look of mild horror. Bread comes with most meals but is not meant to be dipped in olive oil before the food arrives — that is a foreign invention. The menu typically runs antipasto (starter), primo (pasta or risotto), secondo (meat or fish), and dolce (dessert). Most Italians do not eat all four courses at every meal.
Pasta. Every region has its own shapes, sauces, and strong opinions about whose are better. In Bologna it is tagliatelle al ragù — not spaghetti bolognese, which doesn't exist here. In Rome it is cacio e pepe, carbonara, and amatriciana, all made with guanciale (cured pig cheek) rather than bacon. In the south you'll find pasta dishes made with dried pasta and tomato-based sauces; in the north, fresh egg pasta and butter or cream sauces are more common. In Naples they will tell you pizza is the thing, not pasta, and they are not wrong.
Regional specialties. Emilia-Romagna is the acknowledged gastronomic capital: Parma ham (prosciutto di Parma), Parmigiano-Reggiano, mortadella from Bologna, fresh tortellini, and traditional balsamic vinegar from Modena are all made here. Tuscany offers bistecca alla Fiorentina (a huge T-bone, charcoal-grilled, served rare or not at all), ribollita (a bread and vegetable stew), and the local Chianina beef. Piemonte has white truffles (season: October–December), Barolo and Barbaresco wines, and tajarin, a very thin egg pasta. Liguria gives you pesto alla Genovese — the original, made with small-leaf Ligurian basil and pine nuts. Sicily has its own world entirely: arancini (fried rice balls), pasta with sardines and wild fennel, caponata, and the best street food in Italy.
Wine. Italy produces more wine than any other country, and almost every region has its own DOC and DOCG designations. The most celebrated: Barolo and Barbaresco (Piemonte), Chianti Classico (Tuscany), Brunello di Montalcino (Tuscany), Amarone (Veneto), Sagrantino di Montefalco (Umbria), and Aglianico del Vulture (Basilicata). House wine in a trattoria is generally cheap and perfectly drinkable. Don't sniff at it.
Eating out. A trattoria is a family-run restaurant with a short menu and no pretension — usually the best option. A ristorante is more formal and expensive. An osteria is originally a simple wine bar with food; the word is now used loosely. An enoteca is a wine bar, often serving excellent food. Avoid restaurants with photographs on the menus and touts in the doorway near major tourist sites — these are almost always bad value. Lunch (12:30–3pm) is cheaper than dinner; many trattorias do a fixed-price lunch menu (menù del giorno) that represents excellent value.
Coffee culture. Standing at the bar for your coffee is the local custom and usually cheaper than sitting at a table. The surcharge for table service can be substantial in tourist areas. A cornetto (Italian croissant, less buttery than the French version) with a cappuccino is a perfectly good Italian breakfast.