[roey2009]

I would recommend books. Psychology (Deep Work Rules, Thinking fast and slow) , sociology, theology (Buddhist, Confucianism, Tasoism, Alan Watts), Ethics and Philosophy (Stoicism, Ego is the Enemy, Bruce Lee), Communication Techniques (Non-Violent Communication, Brief)

etc, etc. Eventually, constant shared truths that you will find in all of these fields will occur to you, and you will develop an organic leadership based on grounded knowledge of yourself.

Everything else is either a band aid or supplementary, in my opinion.