In poker, a “tell” is a change in demeanor or posture that offers insight into the kind of hand a player has. If Morgan’s eyebrow twitches at the sight of a pocket pair, it’s a tell.
Writers look for something similar in spirit as they try to depict an epiphany. Nobel Laureate James Joyce defined an epiphany as “a sudden spiritual manifestation, whether in the vulgarity of speech or of gesture or in a memorable phase of the mind itself.” If I were to describe a character as standing pigeon-toed, leaning against a wall, head down, hands in pockets, you might infer that the person was shy or fearful. Good writers use a character’s body language to tell you everything you need to know about frame of mind.
Look around you today. Watch people carefully. Give some examples–without naming names or violating confidences–of epiphanies.