Eat That Frog!: 21 Great Ways to Stop Procrastinating and Get More Done in Less Time

by Brian Tracy

20 percent of your activities will account for 80 percent of your results, 20 percent of your customers will account for 80 percent of your sales, 20 percent of your products or services will account for 80 percent of your profits, 20 percent of your tasks will account for 80 percent of the value of what you do, and so on.