Wikipedia summarizes the Pareto Principle like this:
The Pareto principle (also known as the 80-20 rule, the law of the vital few and the principle of factor sparsity) states that, for many events, 80% of the effects comes from 20% of the causes.
To some people, this seems to suggest:
20% efforts =>
80, 90, 99% results! WOW!
It is easy to fool yourself into believing all that matters were those 20%. Once you believe that, however, the Pareto Principle becomes kind of a voodoo ritual: «Hey, just find the 20% of your actions that really matter. Pin them down (pun intended) to make almost all of your dreams come true.»
A few frustrating experiments pass by and disappointment kicks in, because the Pareto Principle apparently just doesn't «live up to its promise». So the 80-20 rule must be «useless», because it can't «tell» you where to pierce the doll.
Take one step back to become aware of how fixated one can become on the 20% part of the rule. Just find those 20%, the most promising actions that target.... ummmm: what exactly do they target?
Where did the 80% part go? It nearly vanished. Well, anyway it's just a negligible deviation from complete fulfillment, isn't it?
The 80-20 rule, however, is about looking at your goals first, before taking action. The first step is to condense
must haves + essentials + nice to haves + crazy ideas
must haves + essentials
To put it in a nutshell: boil down the flimsy soup of goals to an 80% concentrated stew that will give you the power and wisdom to act effectively.
That's the open secret of the 80-20 rule. It starts with the «80», and so should you.