I prefer to use as much super glue gel as possible, the largest bead that I can get on it without covering up too much of the coral. I really don't want to lose my frags!
Oh, and also, before you stick a frag somewhere in the tank, be sure to brush the area off with your finger, fingernail, and/or toothbrush, to ensure that any turf algae or detritus that is there is gone, so it'll be glued to the rock, not what's covering the rock.