The rule of three is simple.
Pick three things you want to achieve today. And focus all your efforts on those three things.
By doing this, you end up clearing your task list much faster than you expected, you’re not as drained, and you’re more relaxed, because you only have three things to do today. The bonus is that when you’re more relaxed, your performance and output increases exponentially (there are hundreds of studies on this to prove it) and by achieving these three things every day, you’ll feel an overall satisfaction with your life.
A good idea is to make one of those three an item you’ve been procrastinating for a while. By ticking it off, you’ll be encouraged to tackle more on your list, which is always a great thing.
A bonus tip is when you’re finished with those three tasks and you have the time, don’t stop there. Tackle a fourth, or perhaps a fifth. And do keep track of your progress somehow so that you can reward yourself for all the hard work!