Expect chaos: It’s the kind of chaos that you wouldn’t expect in the capital of a “developed” nation. Or that perfect city that Caesars ruled only a few hundred years ago. Yes, those parts of the city built a thousand years ago are still awesome and totally worth it. But the surroundings… oh my God! There’s ugly graffiti everywhere, random stick on “bahumulya mat daal kar vijayi banavein” pamphlets deface almost every outward facing wall, even residential ones, even hotels! Especially in the northern part of the city. Even official notices in metro stations are simply pasted on the wall in cheap printouts. The metro system itself is unlit and dirty and the signboards keep pointing you to the wrong direction. It makes you feel really sad, they’re completely ruining the legacy of Rome.
Get a Roma Pass: If you’re there for around 3 days or more, get a Roma Pass. It might be worth it even for 2 days. You can get them at the Punti Informativi Turistici (tourist information centers) at both airports, Stazione Termini (the main metro/train station) or near many of the other tourist sites. All the details about the pass are here. Basically, for 25 euros per person you get a pretty helpful map and guide unlimited travel on the metro line and the local bus system for 3 days, you get free entry to the first 2 sites you visit (if you choose the Colosseum as one of the two, you’ve already recovered half the cost as entry costs 12 euros) and reduced ticket prices for all sites and museums after. There’s also a separate entry point for Roma Pass holders at the Colosseum (and probably other sites as well) and we saved a couple of hours of waiting-in-line time there!
Book tickets to the Vatican online: This is probably the most important tip. Go to the online Vatican ticket office and buy tickets to the Vatican museums (including Sistine Chapel) online. Seriously, make sure you do this. There are limited online tickets per day but if you’re planning a holiday in Rome, you’re probably doing advanced preparation anyways. So go to the site and reserve admission for yourself. Judging by the size of the queue when we got there and the speed at which it was moving, I think it would take you about 6 hours of waiting (and the Vatican gates close at a fixed time) before you actually gain entry into the gates of the Holy See. Guess how long it took us to get in with prior reservations. 3 minutes.