We were in Rome and Pompeii this summer. My best hints:
Rick Steeve's travel guides. Good, lower cost hotel recommendations - we stayed at a cool place walking distance from the central station and right on the main bus routes.
If you are in Rome for more than one day, get the Roma Card (TI in the central station). Transit on all the buses and subways, two admissions to the big venues (coliseum, etc.). With this card we bypassed this enormous line to get into the Coliseum (learned about in the Rick Steeve's book).
We splurged on a private guide for the Vatican. Made a huge difference. There are also ways to avoid the huge lines there - go in through the museum, there's a security line but once you are in you can walk directly through the Sistine into St. Peters.
Pompeii was much more impressive than we expected. Watch for rain since it is all outside. Just be careful on at the Roma train station (I got hit by the usual cute gypsy girl in miniskirts reaching into my pockets. I waited an extra minute before yelling. True story.).
Let me know if you have any questions while it's still fresh in my head:
