2. That said, invest in a good street map beforehand. Particularly if it has interesting tips and historical facts.
3. Watch Roman Holiday and track down the spots where Audrey Hepburn and Gregory Peck went.
4. Italian food is divine. Italian restaurants are not. Overpriced and with disappointing quality, stay away from any tourist cafe or restaurant near main attractions (so, basically all the restaurants). That said, here is a link to one woman's favorite places...
7. If you can, go in the spring or fall. August is awfully hot and most shops (and night clubs) are closed since the Romans are all on vacation themselves.
8. Grattachecca. Found only in Italy's capital, this shaved ice, fruit juice and fresh fruit chunks is hands-down the very best way to quench thirst during the torrid August days. The best, and oldest, one is lemon and coconut. You shouldn't pay more than about 4 euro for one (at the most).
10. Explore at night and learn some Italian. Not only is the temperature a good 10-20 degrees cooler, but seeing the ancient monuments lit up is breath-taking, and this is when you'll get to meet new Italian friends to explore with.
11. And go with your best friend. :D