Sorry...forgot to answer!
I will say that it is very difficult until you fully understand the chemistry and biology of what is going on in your tank. Water quality is key, using biological filtration which is bacteria that live in the live rock and live sand, and mechanical filtration such as a good protein skimmer. Circulation is very key in order to replicate ocean currents and keep detritus from settling.
Another HUGE thing is lighting. Corals are photosynthetic and need intense light to thrive, particularly stony, branchy corals. My aquarium light would give even you sunburn, Jamshyd.
Once you have the water quality established and up to par (0ppm NH3, 0ppm NO2, 0ppm NO3), then it is up to giving them the other essential nutrients that they need. First and foremost, corals need calcium, an alkalinity supplement and magnesium. When kept within certain parameters, corals are able to use these elements to build skeleton and grow. My corals are growing like crazy. After that, supplements such as strontium, iodine, and various amino acids enhance them even further, but are still necessary. It's all about finding a routine and keeping it stable. Unfortunately I don't have a peristaltic dosing pump array (I covet them) so I can't continually dose my 2-part alk/CA supplements or top off evaporation so I have to do it manually. Here are my water parameters as of last night.
Salinity 1.024
NH3/NO2/NO3 0ppm
Calcium ~420ppm
Alk 9-10
Magnesium ~1280
Those are pretty ideal conditions, but you do have to keep on top of them in order to maintain the stability. It's a commitment for sure. When I have the money I will definitely automate my next tank as much as possible.