Every situation is different... of course....
I have set people up with handheld mics in the control room, on the couch, under the console, in the live room with a standard setup, but like 27 candles and tea and scarves and a teddy bear... whatever it takes. One thing though that I have found works quite well (usually) is to just double and triple and quadruple the vocal during tracking only, then comp from those "double's" and "triples."
Basically, take the weight off of any one performance, so the singer can relax. Force them to relax with a disorienting flurry of multiple takes, then settle back into a more comfortable pace, but still letting them hear a little of what they have already done. Nothing like having 4 of yourself to lean on, so you are not "out there alone."
This can work wonders. Sometimes the third "overdub" becomes the main vocal because it is just so relaxed, but with the right kind of energy,.... These are general terms... Hope that helps for some reason...