Is it really about effortlessness? Doing things without effort is easier said than done. What is the mark of doing something without effort? It is MASTERY and you don't master something without effort - in fact it requires tremendous efforts.
Effort - LESS - ness.
LESS effort, not NO EFFORT.
When you have mastered something, you get a great result from doing little effort. But actually this 'little' effort is not small- it is just the right amount of effort required for the action to be done. This is a high level of efficiency and thus Mastery. This effort is small in comparison to the huge efforts wasted by unskilled action.
Modern Humans are in a constant state of tension - both mental and physical. This creates a lot of unnecessary tension, friction and disharmony in one's life and in the world. Effort is required for anything to happen- there has to be an energy exchange/transformation in the physical world. The source of this energy is your own; your life energy. Don't waste it! Don't waste effort - don't waste Life!
And thus, putting effort in the right place, instead of not making any effort at all, leads to effortlessness. This is because it requires effort to let go of your tension, to let go of of the multitude of thoughts and unnecessary noise. Put your efforts in the right place and THEN things will become easier. Let go of the unnecessary stuff.
If Mastery is refining a skill to a high degree, then Mastery in itself is mastering the one (the being) learning those skills. In fact, whenever you Master - ANYTHING - you are mastering yourself.
So remember, if you want to make less effort and make your life easier, find the right places to direct your efforts; your Life. Among the chaos and the noise, finding the right path toward this gold is an aspect of mastery in itself.