There are six primary drivers of organic revenue growth:

1) Customer Retention
- Keep your current customers

2) Customer Expansion
- Sell more stuff to your current customers

3) Market Penetration
- Sell your product or service to new customers in your current market

4) Market Expansion
- Selling to new customers, in new markets

5) Product Expansion
- Sell new products to both new and existing customers

6) Pricing Optimization
- Sell the same stuff, for more money

Most SMBs lose sight of their most valuable asset, their current customers. you've already paid to acquire them, and they've already opened their wallet to you.

#1 and #6 are the 'easiest' (relatively speaking). If you can master just those, you will have a very successful, and profitable business. 

If you can master 2-5, you have an exceptional business that anyone will buy for a great number.