Hardcore players of Super Mario Bros are some of the most skillful gamers around. The number of specific inputs they must do in certain order and at certain times to correctly perform the "tech" is a work of art in the gaming world. Many will require to master these techs if they would dive deep into the Kaizo world.
During one of his livestreams, Mario streamer Grand POOBear, or David Hunt (if his imdb page is to be believed) answered a question from his chat stream, asking how to get better at inputs.
POO said: "You just play a lot - I don't know, you play a lot of games and then you - I mean, what you got to do is push yourself to play levels that you think are too hard for you. And just spend hours and hours and hours and hours and hours and hours on them, and eventually what happens is those levels become very easy for you. You know what I mean? At least the first part of it. But you know, you get better and better at the level and you become more and more consistent. And then, once you've done a few of those, like you've kind of seen them all, if that makes sense. It's just pressing those same amount of buttons in different order."
In short, practice a lot. If you have Super Mario Maker you can begin your Kaizo training with CoolCat's basic Kaizo training - course code is B917 - 0000- 0325 - 62F1
Or, if you're brave enough, you can take on one of the hardest Mario Maker levels available right now so everything else will be cakewalk. Pit of Panga: U-Break with the course code BC5E - 0000 - 00D4 - CD7C
You can check out more of Grand POOBear on his YouTube channel, which are summed up streams from his Twitch channel. Currently, POO is attending the 2018 Summer Games Done Quick for the Super Mario Maker 3v3 Blind Level Race with other Mario behemoths - CarlSagan42, GlitchCat7, Failstream, Jaku, and Cliffy, scheduled on the 1st of July.