Good stable environment. Good gardening practices like proper watering and fertilizing (potting soil grow) and decent genetics.
And then a lot of practice with your system. I haven’t changed much in 4 years now. Those are all feminized seed plants staggered about 10 days apart for perpetual 1 plant at a time harvests.
The ed Rosenthal Grow book has all the info needed to set up a perpetual garden and produce big potent buds. I started there for info.