What strategies can a startup use to boost small to medium enterprise sales?

There are so many articles on how to crack enterprise sales but I could not find any on small to medium enterprise(SME) sales. Any creative suggestions on how an early stage startup can crack SME sales?

Would be interesting to know how companies like QuickBooks, Xero, Square and Apple (sold PCs to SMEs in the beginning) were able to grow so fast. SaaS startups too!

Thank you!