So here are two strategies:

Follow the money
You need to go where the money is spent on developing/design. I would approach startups at WeWork and also get in contact with the MBA programs of the universities in NY. Instead of giving a better price (finders fee) to actual projects build the relationships with those that will start startups. If you build their first project successfully then you would have started a long term relationship with someone that will have many years in front of them needing development work.

I will also approach Angels/VC and let them know you will give a good price to portfolio companies that get referral by them

Follow the volume
Accelerators/Incubators: Go to where the volume is: remember that the conversion rate on leads is small. Focus in the places where many projects will be built and where you can find those guys that don't have the technical skills.

PS: This are not strategies I did but I would if I was in your situation. :)