Your question needs more "meat". What service/product? What verticals? No details needed.
Anyways, the basic answer to the basic question is: go into it like you did the first vertical. You lathered, you rinsed, now repeat. :) Don't assume that this new vertical will be sold the same way, be processed the same way, be maintained the same way, etc.
However, as being the recipient of "the magic of cashflow" (hopefully!), some options you didn't entertain before, due to not have the resources for it, should be brought back out and reconsidered.
I lived an example as we added a healthcare vertical to our established real-estate clientele. Prospects had different needs when being sold, the services had to be tweaked to meet regulatory constraints when the real-estate market had none, our systems had to be expanded in functionality to meet different reporting needs, etc...