It takes time. People are also different.
I tend to lower the lower the power and higher the higher the power as a % of ftp. Very generally stated.
At first try to do the tougher work at a higher cadence and more SS work at a lower one.
No magic formula but 85 to 105 seems to be "it" for most folks. People do all sorts of workouts really slow or one legged and things, just ride man. Ride freaking hard. Your personal body will figure out what it prefers when the chips are down for each situation.
I do vehemently disagree though that cadence won't improve power delivery on its own if someone is way out of range to start with. If you're in the 60/70 range to start with, bumping up some would be a good idea.
Listen to up-tempo music with obvious beats.
At hour power I'm usually around 100. Pursuit power and higher, all bets are off. Could be 95, could be 110. Hill, flat?
Ride enough you can play with it too.