Train to help a disabled runner. It's a very memorable experience to be a guide. Turn in your number if you decide not to run. You'll be guaranteed a spot in next year's marathon. Allow yourself time to train.
Experts recommend at least a year of regular running before undertaking a marathon.
Understand that your odds of getting in may not be particularly good. Over 30,000 would-be New York City Marathoners are unable to run because of the limit of 30,000 entrants. Follow the rules. Never run with someone else's number or give your number to another runner. If caught, both runners will be disqualified and barred from all future New York Road Runners Club events.