Plan early. Unlike mass at your local parish, Christmas Eve mass at the Vatican is very popular and requires tickets to enter the church. If you allow yourself enough time to plan your trip and request tickets, you will avoid the last minute hassle of trying to find tickets.
Know the limitations the city of Rome has to offer during that time of year. Like America, that is a very popular holiday season, but in Rome most of the city virtually shuts down or runs on a very limited schedule. From Christmas Eve until after New Years, there are very few restaurants or shops open and most people are with family.
Arrange for someone to pick you up or plan on walking back from the Vatican. The mass begins very late and will end around 2 a.m. Public transportation and taxi services stop at 11 p.m., so unless you have arranged alternate transportation with someone you know, walking home will be the only option you have.
Put your wallet away and take your confirmation with you. Tickets are free, but not mailed to you, just the confirmation is sent. Tickets can be picked up two days before or anytime up until the evening of December 24th. You will need to stand in line to pick up tickets, but know that the line can be incredibly long so plan enough time in your schedule to allow for these lines.
Arrive early to get into the church. Although St. Peter's will not open until 11:15 p.m., people begin lining up for entry around 9 p.m. It is very cold at night in Rome during the Christmas season, so bring along warm clothes and expect to wait in line before the service.
Don't despair if you were unable to get tickets. There is another line of people at St. Peter's who don't have tickets but want to attend the mass in St. Peter's Square. Thousands of people choose this option, so arrive early, dress warmly and plan to be in large crowds all night.
