I usually only do 2 things. 1) I'll dip them in Coral Rx or Thrive to "clean" them. It's something I've always done and can help eliminate some pests but if that's a worry, there are better options. But I dip with the two I mentioned whenever I get a new one or if I have a frag that's not looking too good. 2) I'll keep them lower in the tank so they can heal up without getting blasted with light. It's a good idea to acclimate all frags to the higher parts of your tank but I'll keep frags a little lower even I know they came from a higher light system to give them a little adjustment time.
As far as any sort of extra supplementation, I just treat them like everything else in the tank. If it's an LPS, a little mysis or brine once in a while and a powdered reef-roids type food when I do the rest of the tank.