Any tips/tricks you learned?
Don't skimp out on filtration, especially once you decided you wanted corals and nems.
Both of those tend to be sensitive to nitrates and phosphates, in my experience. My first saltwater tank had a built-in filtration system that worked just like a normal HOB filter and I was battling nitrates and phosphates from day one, even with very light feedings. Unlike a planted tank there was simply no where for those waste products to go except for during water changes. I tried all sorts of cheap and easy options. like adding Purigen or PhosGuard to keep levels down and they simple didn't work. One day I was able to find a tiny little protein skimmer that fit in the filter and that made a big difference. Within a day or two of running the mini skimmer my corals showed the best polyp extensions and colors. Having the skimmer removing the nitrates and phosphates also meant I was able to reduce the amount of water changes, which in turn meant less money spent on salt mix and less time fooling around making new SW.
I had two other SW setups, one with a sump and one with a refugium hanging on the back. The refugium was filled with chaeto algae and did an ok job of removing nitrates and phosphates, but the tank was just too large compared to the refugium for it to be as effective as I wanted it. The other tank, the one that had the most beautiful corals and all of my flower nems, was attached to a little 10gal sump. I had a limited budget so I had to DIY the sump and plumbing, it was a bit of a pain and there was a bit of troubleshooting and trial/error involved, but in the end I had almost zero algae in the display tank and my corals and nems looked absolutely amazing. I could sit there and feed my nems and corals to my heart's content without worrying about nutrient spikes. I was able to keep my heater, protein skimmer, and a large chaeto refugium all hidden away under the display tank.
For coral foods I used Benepet's Benereef powder. My corals loved it and it did not foul up the tank like other foods did such Reef Roids. American Marine's For my picky fish I would use Reef Nutrition R.O.E. eggs and would soak the eggs in American Marine's Selcon liquid vitamin to ensure they were getting proper nutrition. I would also feed a lot of krill. Lots and lots of krill. I would get the big frozen packs of whole krill and would thaw out a krill or two for my nems (smaller chunks for flower nems and whole krill for my bubble tip), again soaking the krill in the Selcon vitamins. I also took made a cocktail for the corals by thoroughly blending krill, ROE eggs, Benereef, and Selcon together, then pouring the concoction into little mini ice cube trays. Then I would take one little cube out for feeding, thaw it in a shot glass with some saltwater from the tank, and then squirt it into the tank right at the corals with all the pumps off so they had time to really collect and chow down on the food.