Shape up. Eat light meals, abstain from alcohol and avoid overexertion. Though absolutely stunning, the environment is rough. High altitudes, bone dry air, and varied temperatures wreak havoc with the body.
Follow the rules. The people and government of Peru are very generous in sharing their country's natural wonders. Good manners and good sense dictate you follow their rules. For example, don't take anything from the archaeological site.
Acclimate to the altitude. Spend at least two to three days getting used to the thin air in Cuzco, the city from where most travelers begin the road to Machu Picchu. Cuzco is over 10,000 feet above sea level.
Plan how long you want to stay at Machu Picchu. You can’t spend the night there, but you can go back the next day. Alternatively, you could spend a few hours and then head out. Pack according to your plans.
Reserve a train ticket. The train from Cuzco to Agua Caliente takes four hours and tickets must be purchased in advance. The trains leave early in the day. There are agents all over Cuzco who can help you with reservations.
Board a bus at Agua Caliente. The bus terminal is a short walk from the train station. You can’t miss it. From Agua Caliente the bus ride, under 30 minutes, is windy and twisty. Enter the site. From the bus, you’ll be left off at Machu Picchu’s entrance. Explore, enjoy and marvel.