Choose shoes that are well-cushioned and comfortable for standing for long periods. Avoid minimalist shoes or sandals that are not cushioned.
During summer time bring: sunglasses, a hat and a bottle of water that you can refill on the plenty fountain’s of Rome.
During winter time bring: umbrella, jacket or a windbreaker.
During the tour you would be probably visit a church where admittance, as in the Vatican Museums, the Sistine Chapel, St. Peter’s Basilica and the Pantheon, is permitted only to appropriately dressed visitors.
Inside the Churches low cut or sleeveless clothing, shorts, miniskirts and hats are not allowed so remember to bring a scarf to cover your shoulders before enter inside.