Ok, here are my top 10 tips for "newbies":
1. Smile!
Seriously.... have fun and be amazed at yourself!
2. Trust your training.
3. Get on the bus/monorail early. Hurry up and wait is the name of the RunDisney game.
4. Pre-hydrate, but don't over-hydrate during the race.
5. Keep to your planned pace/intervals, at least for the first 2/3 of the race. You will be tempted to start out too fast thanks to adrenaline and other princesses, resist and "Run Your Own Race".
6. Remember "the relentless pursuit of forward momentum" just keep putting one foot in front of the other.
7. Don't wait in too many long character lines if you are close on pace. Remember you can also get pictures with characters AFTER the race, and with your medal!
8. Pack your running gear in your carry-on luggage.
9. If you tend to be a salty sweater, consider having a spectator bring pretzels or tortilla chips to the finish line for you (or in your gear checked bag).
10. Don't be afraid to chat with other runners before the race, or during! Especially those whose costumes make you smile.