One or more edges that one has full confidence in.
An edge includes entry, exit, trade management and appropriate risk for the times it will take losses.
Full confidence means that there are no psych issues - if they are there then work needs to be done to understand the emotions/thoughts driving them and get past them to the point where you feel confident about the edge and only reasonable fear and exhilaration when executing it.
I don't believe that you manage your emotions: you adjust your thoughts, work on triggers, and change your behaviours after which emotions will become reasonable.