Is tough. Not really. It can be. Sorta. Usually there are free drinks (though I don’t typically drink anymore), well dressed people, and expensively manicured venue spaces. There’s glitz and glamour and nobody can really see anyone’s pores because no one can really see each other (it’s dark).
This being said, to live and hopefully-not-die as a photographer in New York City you need:
Point it at the ceiling and keep your bounce card up. This is what I generally defaulted to, universally, for every shot for the first four or so years of doing event photography in the city that never sleeps. People occasionally don’t use their bounce cards and go for that more natural look, but keep in mind that when doing so your only source of light is going to be the ceiling. This being said, shadows under the eyes, noses, chins, cheeks, etc will be way more visible, and unless you’re photographing someone with porcelain skin, less flattering.
This goes along with the flash and generally determines what the exposure is going to be. You could have your camera set to ISO 1000, F4, and 1/100th of a second. You could later set it at ISO 800, 1/200th of a second, at F2.8. You’ll get the same exposure either way, since your flash is determining actually how the photography is going to look.
Preferably a full frame camera
It’s dark. Cropped sensors don’t like the dark. They like bright, sunny, nuclear-fueled days. Otherwise things tend to get noisy.
I still default to my 50mm half the time; especially when the lighting conditions are somewhere mid-range. If it’s dark, but I’ll still be able to pick up ambient, the extra stop between 1.4 and 2.8 is a gulf.
Lower your shutter speed to about 1/30th of a second, place the flash on rear curtain sync, and you’ll be able to soak up ambient for a moment. After that moment’s passed, the flash will fire and your subject will be frozen and someone somewhere will award you top marks, a trophy, and a several hearty handshakes. ‘Cause you’re a dope event photographer.