Professional trader know the methodology of trading. Most skillful trader didn't trade with emotion they have their predetermined exist plan and have good trading plans.
The most skillful trader is the insider trader, you can study 2000 books but trading is always a mystery, especially bitcoin trading
But if a person study deeply about trade and learn all the tricks involve in trade and he will have a very good intelligence then he will be a very expert trader and will not lose any penny in his trades. All you need to get knowledge you will be professional.