Directory of Associations
You can search for websites for trade associations through a portal provided by the American Society of Association Executives (ASAE):
It's come a long way, as you can now search by numerous methods (like "Association name contains," which is particularly handy). If you need it, you can also search for trade groups based outside of the U.S.
Note that there's also a State field. If you're looking for trade groups with a headquarters in New York State, then this is the field to use. However, I'm assuming that most of these associations will have national or international scope. The National Restaurant Association is based in Virginia, but would still be useful for New York State-based restaurateurs to know about.
So, if you haven't already done so: bookmark this site, no matter what age you are.