Best thing is Stability...end of story.
Seriously it's the beginning of the story, as long as you can keep your parameters stable you have a great foundation. Do everything else in moderation and you can really dial in what's best, best color, best growth or somewhere in-between.
I've seen many healthy, well colored up SPS tanks and chancers are each one has a different story like high nutrients, low nutrients, high ALK, low ALK, success with salinity at 1.023 or maybe 1.026. Every tank has a story and here's mine...
Salinity - 1.025
Alk - 8 dKH
Cal - 460
Mag - 1350
NO3 - .4-.6PPM
PO4 - .02-.03PPM
Tank is an 80g Deep Blue 16" X 24" X 48" and it's an All-In One (total 80g). I have a Tunze DOC 9410 Skimmer and run BRS ROX 8 carbon in a media reactor and I do two 10g water changes weekly. I also dose EVS Bionic 2-part with a GHL Doser. I use an ATI 6 bub (all Blue+ bulbs) Sunpower with a couple Reef Brite and a coupe generic 470nm LED strips. I'm getting 450+ PAR a couple inches from the surface and 350 about 8" down. And flow, lots of it. The return pumps push 800+ gph and I'm running Maxpect Gyre 250's at 50% in alternating gyre mode.
Im in the process of raising my NO3 to 5PPM to help bring out more color and growth. Just started this experiment and moved the NO3 level to 1PPM just today. Here's a few pics of some frags growing out in this tank.