I would highly recommend segmenting your market and really narrowing it down. Pick one niche of SMB and custom-tailor your product to them. The more you can narrow this down, the better (by geography, # of employees, revenue, industry, years in business, age of owners, etc).
The reason for narrowing down the market is so that you can really understand your customer. You need to know their business inside and out. It's those minor nuances between similar market segments where the juicy opportunities are.
For instance, realtors in a primarily tourist areas are quite different from realtors in primarily middle class, white suburban areas. The home buyers are very different, which require different approaches on the realtors' part.
Once you pick your niche (say < 40 room mom-and-pop hotels in summer vacation destinations in the southwest), then figure out what other functionality you can add into your existing functionality that creates some synergy.
For instance, if they use (i.e. pay money for) an email manager (like constant contact), then figure out how to tie your social media manager into an email manager.
This is a much easier sell: 'You already pay $10/mo for Constant Contact. It doesn't allow Social Media management. Our product costs the same, has all the functionality you use in Constant Contact. Plus it manages your social media for you'.
The hook is an existing product they pay money for. Then replace that product with your product by adding some new sizzle.