If you are in between apartments in New York City or you are looking for short-term living options, you have exposure to many types of apartments and availabilities.
There are many places you can look for a sublet. Oftentimes, your friends will send out random emails about them or their friends needing to find a subletter for a short period of time. It's probably best to try to live with someone who you know or a friend of a friend so that you don't have to worry too much about security or trusting that person. This can be a big difference between living with someone you know and don't know.
Another good option to find sublets is using Facebook. Facebook is close to the friends of friends email situation but usually gives you more options and you can if you're linked to anyone through the poster of the listing. This can be very effective at finding availabilities of people who you may have some sort of connection to.
The mecca of sublet listings is craigslist. New York City sublets number in the hundreds each day and you can pretty much find whatever you're looking for. You can search by borough, by neighborhood, minimum and maximum monthly rent, number of bedrooms and any keywords of your choosing. The possibilities are endless. However, with this option, you have to be comfortable living with someone you might have no connection to, unless you get a studio apartment.
Finding a sublet in New York City is a relatively easy way to find housing. Just use one of the few ways listed and you'll find what you're looking for. Good luck.