The 80/20 rule is one of the most important principles you need to understand if you want to succeed online.
It will dramatically improve your targeting, your copy, your sales conversions of online products / programmes. It will help you reduce your marketing costs and build a business quicker.
In this video I discuss why you must master this principle if you want to succeed in your online business and what areas you apply it to.
I highly recommend Perry Marshall's Book "80/20 Sales and Marketing: The Definitive Guide to Working Less and Making More" - click the link below to get it from Amazon.