Meetup is a great resource for events, so that's a good start. Have a look on Eventbrite and other sites to see what sort of networking events are happening in the city. See if there are relevant LinkedIn groups that you can join and use those to find interesting people to connect with. You'll also find that a lot of the bigger/more popular groups will have news feeds with useful links to events and more. Find out what big conferences are on and head along to one or two that are particularly relevant. You'll find a bunch on Lanyrd and other sites.

Ask your existing clients for intros - not leads - but just intros to people they know in NYC. Can they help you get coffee with a few people. If they can and you manage to impress those people, there's a good chance that referral will lead to some work.

Cherry pick some of the people you'd like to work with - specifically ones where you think you could add real value. Reach out to them with a two or three sentence email saying hello and seeing if they have five mins for a coffee. It's never a bad thing to meet more people.

Follow people you'd like to work with on Twitter and build a bit of a relationship with them that way. Use that relationship to potentially get a meeting or a coffee with that person. Maybe they can do some relevant intros or help you in some way.

Be useful - if you're going to meet all these people, make sure that you provide them with some reason for meeting you. Maybe you can intro them to someone or help them with some advice or insight. Whatever it is, make sure that you have something to add into the mix.

Good luck!