password

Judging by the initial question, I'd still say the answer lies in a basic reading material. Without basic knowledge of semiotics and iconology there's no reason to be specific on the approach.

That's not a question to which you'll get a quick answer. Start off with some basic reading material on iconology (Gombrich, Panofsky etc.), then semiotics (Bel & Bryson, Mitchell, Lotman, Curtin). These authors let you dig deeper as they reference other works. But if you're a grad student I'm gonna have to second GhostsBeforeBreakfast here. That's Interdisciplinary Approach To Art History 101.