Here is just a few tips for when in Rome:
1) Italian food is great. Make sure you keep clear of tourist menus though and find a nice restaurant that the locals go to. Tourist menus are designed for tourists. Restaurants that the locals go to want their customers to come back therefore the quality of food and service will be much higher. Often the price is also better.
2) Watch out for pickpockets. Public transport in Rome is full of them. A large number of them are children and when the metro and buses are busy you won't even feel them do it. Make sure you always keep a close eye on your bag/wallet.
3) Seek out the little gems. Rome is full of things to see and art and history are everywhere you look. If you're staying for a couple of days, obviously try to fit in the bigger sites, but if you have a little more time seek out some of the less tourist spots e.g. A great Church is San Pietro in Vincoli (St. Peter in chains) which is located close to the Coliseum. Inside is Michelangelo's 'Moses' (in my opinion, one of his best works).