i think psychology and knowledge about risk managemnt is the most important thing for traders
a lot of traders lost their money because they don't know how to manage the risk in their trading activity
regards
I WIll like to explantiate and broaden your claims.
Psychology deals with the traders mindset and overview of the market space, while knowledge is what we have learnt as a trader, put to practice, and dedicated time to relearn it.
The perfection of the learning process leads a trader to having a trade principle