Summary: Connect Buyers and Sellers within a Niche.
Step 1 - Find a way to Reach a Niche (Trade Magazine, Mailing list)
Step 2 - Find vendors who sell to that Niche.
Step 3 - Connect the Niche and the vendors utilizing Step 1
For example lets say your Niche is Realtors
What do they Need? Business cards, Brochures, Leads, Training etc.
Create a Realtor Resource Directory with vendors that sell to Realtors
Charge the Vendors to be in the directory.
Offer the directory for Free to Realtors though Direct mail, Advertising in Realtor Trade Magazines etc
I am currently doing this in two niches and it works!