In order to master the mind there is really only one essential skill. That is developing the ability to witness the mechanations of mind without resistance or attachment to thought, feeling, perception, and phenomena.

You don't need to sit and meditate to develop this skill but it can be helpful. Witnessing in a detached way, you no longer create an "I story" around thought, feeling, perception, or phenomena. Whatever is being done, 24 hours a day is the practice.

Mastering your mind is proof of work.