Don't leave home for Rome without checking these two blogs.
You can visit Ron in Rome's website or sign up for free delivery of such timely tips as where to find public bathrooms in the city, how to use the bus system, and what passes should be booked ahead of time. David and I have found his information invaluable.
Revealed Rome, written by an expat American woman in her 20s, is also chock full of helpful information. Amanda Ruggeri says her site will help you discover, "Tips, tricks and things not to miss," about Rome. I now know never to ask for Parmesan cheese in a restaurant!