The basic process starts w/reflective listening, then goes deeper to get at the underlying wound ("when you do that, it brings up all the times my parents..."), then to what might happen in a perfect world ("the toothpaste cap would magically fly back on the tube after 30 seconds of inactivity"), then to some concrete make-ups.
The other things we do that helps is to stick with the current argument (which I find difficult, sometimes) and to not go "meta" ("see, honey, there's a pattern here where you ...").