When I was getting ready for my first race there were a few things that my lovely wife told me that I had to keep in mind to be a courteous runner. She said that I did not want to be that one person who violates the rules, even though I was a new runner I was still expected to know the rules of the road as it were.
Running a race along with several hundred or thousand folks tends to present a few problems. The following rules will help to keep you out of trouble and help you to enjoy the event with your fellow runners.
Position yourself by your ability - in other words dont stand at the front of the race pack when you are like me and slow as an old turtle, don't do it, don't even think about it. I know that I am a pretty slow runner and because of this I position myself towards the rear of the pack. This allows me to stay out of the way of the faster runners while still being able to have some fun. If you are worried about your time, don't be. Most races give you a race fob that goes either on your shoe or on your bib. Your time starts when you cross the start line, not when they sound the horn.