My favorite fighter is Vasyl Lomachenko. Best P4P fighter in the world today.
While most boxers do the sparring, roadwork, cardio, etc NoMaschenko has taken Ukranian dance as a youth, done sambo and other martial arts, does swimming and other endurance building exercises and to top it off he does cognitive and reactionary exercises. And then he has his dad/trainer fine tune him.
I've learned to do other things besides the usual overcoming objections rhetoric. Eating healthy, analytical type research, stand up comedy, exercise, staying around tough, positive people, studying the market moving forward i.e. if you avoid technology you risk being left behind quickly.