Be prepared ahead of time
Unlike apartment hunting in other cities, applying for any apartment in NYC is an intense process that requires a lot of documents. Apartments fly off the market, so it's vital that you have all your documents and finances in order before you even see your first apartment. Give yourself at least ten days to get everything squared away.
When to start looking
Most NYC apartments aren't listed until four or five weeks before move-in day. If you start searching sooner, anything you look at will likely be gone by the time you want to move. However, you can and should look at comparable apartments in high-occupancy, high-rise buildings that have a lot of turnover. The apartments in these buildings will be very similar, so it's a good idea to check them out ahead of time so you can decide if they meet your needs.
Apartments go fast
Once inventory hits the market, the best deals disappear immediately, so be prepared to start searching five weeks before your move date. And if you've missed the boat, and are caught searching the dregs of the inventory, consider couch surfing or a short-term rental so you can catch next month's batch that will hit 4-5 weeks before the 1st of the month.
If you're working with an agent, keep in mind that many won't work with you if your move-in date is months away because apartment availability is hard for agents to predict.
Confirm your roommates ahead of time, and lock down every roommate's information. Each individual will need to provide a ton of documentation, and you'll all need to be ready to act fast. It's essential that you have responsible and trustworthy roommates, and in many ways, securing an apartment will be the true test of how trustworthy your roommates will be.
Choose the right roommates
If you have a roommate who is having trouble putting together all the necessary documentation to sign a lease, chances are that person won't be a reliable roommate. Suppose you sign the lease, and things are smooth for a while. If your roommate hits a rough patch and can't pay his or her share of the rent, then all parties are in violation of the lease (even those who are paying their share) and are at risk for eviction.