Decide on which of Italy's many regions you want to experience on limited time. (Americans need only a passport to enter.) If this is your first visit, travel from north to south to marvel at how the country becomes more disorganized and more provincial. You leave the sophisticated European urbanity of Milan and Florence for the more rustic realms of Naples and Sicily. Rome acts as the halfway point between these two realms.
Though the Mediterranean weather of southern Italy is generally mild year-round, the northern regions can get cold and damp, with snowfall in the Alpine mountains. Summer provides the best weather, the most attractions and crowds, and the highest prices. To combine pleasant weather, lower prices and fewer people, try a visit during May or September. However, Venice can flood almost any time outside of summer.
Consider staying in a major city with excursions to smaller towns. This stability gives you a more accurate picture of a region than rushing through overnight stays from town to town. This is important because many regions and cities were self-contained principalities for centuries and developed their own unique cultures and cuisines.
Train travel can connect your destinations quickly and comfortably. It is also so cheap that buying a rail pass may actually cost more than buying single tickets. You'll need to compare prices on the Italian State Railway site. Car travel may be the only way to reach smaller villages and countryside locales. All you need is a U.S. driver's license. Be warned that driving in the major cities can be challenging. The tension eases on the country roads especially in the rolling hills of Tuscany and Umbria.
Accommodations can be expensive with mid-range rooms starting at $200, though much cheaper, if more depressing alternatives exist in hostels and bed-and-breakfasts. Prices vary according to season, hotel and number of stars but drop if you forego private baths, views and accessibility to tourist sites. Unless you're in an expensive property, be prepared to do without elevators, good water pressure, air-conditioning and customer service.
Rather than trying to decipher an Italian menu, ask the waiter for the local specialty and a local wine. For a cheaper alternative, eat sandwiches and appetizers at a bar. Prices are cheapest standing at the counter, more expensive at a table and skyrocket at an outside patio. Dining is typically slow and unhurried because Italians like to savor their food. You may need to pester your waiter before he brings the check.