Building the trichomes is one thing; filling them is another.
Photosynthesis occupies the plant's oxidative capacity. When it comes time to fill the trichomes, this is a highly oxygen-intensive process. Cannot be done with any efficiency if you are still pushing photosynthesis, occupying a majority of the oxidative capacity, as it's also used to protect the plant from photoinhibition. Must lower DLI enough to allow the oxidative capacity to be used on trichomes rather than still focusing on growth. Failure to do so will have half your trichomes amber before they even start to become glassy and white.
The competition for cellular energy and oxidative capacity between biomass growth and secondary metabolite synthesis is, imo, the single most important factor for final quality overall.
Trichome filling is also very reliant on micronutrients, so it helps to add a burst of humic and chelation efforts simultaneously as you open the capacity. Also, adding a tiny little bit of elemental Sulphur 2-3 weeks prior to flip will give a massive boost towards IPP when it's needed most at critical trichome time. Probably not recommended to use sulfur, though, unless you have the medium/setup to handle it, as it's a funky nutrient that can screw things up easily if the ratio is off.
Nitrogen is a master signalling molecule; when the plant is loaded with it it sends a strong "growth" signal that directs the plant's energy into "growth" rather than Nitrogen tapering initiating starvation protocols. The plant must have initiated correct and proper signals in order to "ripen"; this is done by increasing the ammoniacal nitrogen to 50% for no more than 7 days, then slam a pure N starvation or a PK boost to starve the N and send a signal. Donbe correctly 24-48 hours you will notice the sink/senesceance.
The plant won't produce the finished profile if the ratio of nitrate remains high throughout and up until harvest.
That's pretty much as detailed as you can go without going atomic.