Seriously though, lots of reading with trial and error and not afraid to experiment if/when something isn’t quite right. Imho, the most important aspects are:
Great genetics - many are just poor producers no matter what one does
Decent medium - balanced nutrients given at the right times
20w/sq ft for veg, 40 w/sq ft for flower or close to it
60-70F lights off, 70-80F lights on - no more than a 12F difference between the 2
Exhale bags are awesome for 80-85F temps
Foliars for immediate change
Only aim to impress yourself
Don’t sweat the small stuff - remember by the time a problem is spotted, its been going on for awhile so it will take awhile (~4 days on average) before the correction is seen
Journals are awesome research tools: bush or tree, heavy or light feeder, minimal or triple stretch, training techniques etc
Learn plant communication - slightly droopy leaves at same time every day vs asking for water (stem and leaf droop) vs overwatered (just leaf droop); leaves curve (ph issue) vs leaf turn (too much light/not enough humidity) etc.
Mother Nature is the best teacher - watch how she tends to an area giving drought years vs lush years and how it changes the dynamics favoring one type of plant over another…slow and steady
Each environment has its own challenges so try to shoot for the basics then experiment from there to find what works for you…what works for me could be mildew hell for another