Just read this book by Howard Abell. Bought it for $4.00 after shipping. Has a few nuggets I will share. You can find your own copy at Amazon -- I think there was one other copy for a penny + shipping.
1) Good trading must be automatic. This is why mechanical traders or algos work well -- they don't hesitate and overthink. They react to patterns and take them. The hesitation and overthinking and the forming of opinions is probably what prevents many would-be traders from achieving CP.
2) Intelligence can be a negative.
Intelligent people may be overconfident. They are more likely to think they are right and the market is wrong. Intelligent people may be more prone to forming opinions. And then unable to let go when the market does its crazy thing. They may be creative -- seeing patterns in the smallest jiggles. They may over-analyze, wanting to see more proof and therefore waiting until it's too late to enter a position.
The last few chapters are interviews with top traders. One trader had this very Zen concept that I won't repeat word for word but it was the part that was definitely worth $4. The gist was:
a. When you realize you don't have to know for certain that the market will move a certain way -- only then can you be certain of your trading.
b. You must learn to lose, and accept losses if you want to win.
c. You can only control your trading by accepting you have no control of the markets.
These were the main ideas that stuck with me.