WARNING: Contains gratuitous theory and random acts of name-dropping.
Unless the subject of your piece is theory itself, consider approaching it as you would acting: it’s more effective to show than simply tell. Dropping theories and theorists like they're double entendres in a Restoration comedy simply to prove you know them isn’t contributing anything to the field, and probably isn’t the best use of your limited space.
Similarly, avoid hiding behind jargon. It can be tempting to draw on theory to craft sentences so complex and overdetermined that a reader chalks his/her lack of understanding up to your impressive intellect, rather than your inability to clearly articulate an idea (or your insecurity). Only Peggy Phelan can (or should) write like Peggy Phelan!
To be sure, the nature of the journal should dictate, to a degree, how you employ theory: if intended for a more general audience, a concise overview of a particular theory or a brief lineage of a particular movement is certainly appropriate. But you should only include information that is necessary to tell the particular story you’re interested in telling.
This is one of the areas that's especially relevant when adapting material you've generated as a student. Demonstrating your familiarity with a body of scholarship is essential to establishing your credibility in the context of seminar papers, comprehensive exams, or a dissertation. Publication in a peer-reviewed context, however, implies you've already demonstrated your competency in the eyes of your peers, obviating the need for the same sort of exhaustive documentation. Your use of theory should ideally reveal your mastery of its essentials and your ability to deploy it to analyze a new phenomenon (or, when relevant, to revise or challenge it in light of the new insights your work provides).