Race etiquette is fairly simple. When you line up for the start of the race, try to line up by your anticipated pace. If you are going to run a 6:00/mile go to the front of the pack, if you plan on doing 10:00/mile pace go in the middle, and if you are walking go to the back of the pack. Doing this will help prevent anyone from getting ran over by other runners and it also courteous to the other participants.
Think of running/walking as you would driving: faster runners to the left and slower runners/walkers to the right. If you are using a run-walk-run method or just need a break, pull off to the right when walking. This helps keep the path clear for those passing. If you are passing someone it is courteous to pass on the left side (just as you should when driving).
One final piece of etiquette involves groups. Typical race etiquette is to not run/walk in a group of more than 2 abreast. Yes, running/walking can be a social activity, but for the safety of those around you, it is best to not have more than 2 abreast so others may pass safely as needed.
A lot of runners have to spit while running. The best way to handle this is to pull off to the side, make sure no one is within your "spit path" (take the wind into consideration), and spit. Easy!
What are some questions you have about running/racing? Post your questions below and I will be happy to answer them for you!