It's said that about 20 percent of your customers produce 80 percent of your sales. It's called the 80/20 rule. If you're responsible for sales at your company, you better get to know it.

Why? Because that 20 percent is where you'll get the biggest bang for your sales and marketing buck, says Perry Marshall, president of Perry S. Marshall & Associates, a Chicago-based company that consults both online and brick-and-mortar companies on generating sales leads, web traffic and maximizing advertising results. Marshall is also the author of five books including 80/20 Sales and Marketing and Ultimate Guide to Google Adwords, both from Entrepreneur Press.

In this Google Hangout, Marshall talks in detail about the 80/20 rule and how business owners can leverage it for everything from finding customers, engaging them and selling a ton -- both in-person and online. "In sales, there are all kinds of things that don't appear to be directly connected to whether somebody's going to buy, but actually they have everything to do with whether someone is going to buy," Marshall says.

Marshall also talks about how the rule applies to areas beyond sales, like motivation and time management. 

Related:

The 80/20 Rule of Sales: How to Find Your Best Customers

80/20 Sales and Marketing: The Definitive Guide to Working Less and Making More (Related Book)