I don't know if anyone mentioned this but aside from the basics, lighting, keeping clean, etc. The thing that worked best for me was calc and all. I know that's a rather basic element of keeping coral especially SPS but I don't think too many pay attention to it, or not as much as they could. I'm sure plenty of you do but for the person that just drops good money on a set of halides and starts puttin sps in their tank and expectin them to grow there's a little more to it.
All I did was get a salifert calc and all test kit and b-ionic ESV 2 part calc and alk. For the first month or so I tested almost everyday and would dose what was needed. As the corals grow they suck up more calc an alk. You'll get your dosing down to a T but its real easy an keeps it interesting. I had a nice T5 setup at the time an within weeks of dosing the corals in my tank were growing at a very fast rate. As far as Magnesium goes not sure how it plays into it but mine was always high and my tank never seemed to use it.
I also would throw some trace element stuff in there from time to time.
I feel like growing SPS is directly affected by how much time you put into it. This was a very basic method I used and it worked great.
Just my .02 c