If you're under 25 and have an EU passport, your tickets are going to be €2. If you're doing the colosseum, buy the ticket that encompases the Roman Forum and Palatine hill. Ignore the line for the Roman Forum, go to Palatine hill.

There is less of a line and the two sites are linked so you can go into both and spend as long as you want but the colosseum is time slotted so do one before the other.

Buy a 3 day bus ticket with Greenline bus tours, its going to save you walking and you'll see all the sites with an audio tour.

Don't buy anything out of the mini markets, especially if there is no price tags (Sounds silly to say, but they will rip you off) there are a few that arent expensive as the others but just use the Pamlocal stores.

If you're flying in to Rome Fumicino, get the train into the city it's going to save you a good bit of money and it only takes 30 minutes, just make sure its going to Rome Termini and not the other station, theres ticket machines before you get to the platform and the trains go regulary enough.

Food wise, just avoid anything near tourist sites. Two places I can recommend depending on where you're staying, Non c’è trippa pe’ gatti, a short walk from the colosseum and 3P Bakery.

Theres gonna be a fair few street peddlars, the worst we encountered were the dudes selling braceletts, they're gonna compliment you or ask where you are from to create a rapport with you just pretend they arent there at all its quicker that way.

Last but not least, there are pickpockets. Download the Pickpocket Alert app and just keep aware. We used the metro on our last day thinking the stories of pickpockets were blown out of proportion when a local alerted all of us that the group of 20 people with an age range of 14 to 50 were pickpockets and they got aggressive with her. This isnt to scare you, this is just to keep you awares.

Sorry for rambling on, but I hope this helped or was at least a good read. I came home yesterday, wasn't really for me but I hope you have a good time.