I'll give you some easy pointers that I've realized in myself and with the reactions of those around me.
-I always walk with my back straight.
-I'm hard to approach, but once I have been -- I'm intoxicating (if the conversation has a purpose) or so I've been told.
-I'll correct you without you realizing it -- politely.
-I'm intimidating because of an aura of confidence.
-I use health issues as excuses more than anything.
-I find myself rarely wrong, because I speak only when I'm sure (I'm sure I'm incorrect more often than I realize).
-I look sad
usually two types:
-Sad in the sense I've been wronged (pouty lips).
-Sad that the world had to end, beginning and ending with the stare of grim resolution. (This is what I consider the "INFJ" look). I find people ask me what's wrong more often in this state than in pouty-land.
-When I don't look sad, i.e. smiling, my eyes remain unchanged.
-The girls are all over me because they feel safe having their flirts bounce off me...all due to too high of an expectation on my behalf. I find most of my girlfriends are attracted to me, and to that sexual tension. Apparently it's "Adorable."
-I'm that sensitive and dark guy.
-Quiet, yet my words' meanings carry onward--which was my intent.
-"You should talk to {insert INFJ male's name} about {serious/emotional/deep topic}."
-If I speak longer than a few sentences I mimic monologues, soliloquies, and dialogues I've read before in my mind's eye -- only revised for the situation at hand. It would seem spontaneous to everyone but me (or at least that has been the case for me so far). This makes the moment either epic, or of a bombastic nature depending on the emotional climate of the room and substance of the conversation.
-I'm really sarcastic. Most of the time it's in a friendly way and not directed toward a specific individual unless they deserve it.
-I'm a perfectionist.
-I'm exacting in the things I take seriously.
-I take everything seriously :blushed:
-I'm hurt and at my most vulnerable when I'm staring and standing there, doing nothing, not replying, not caring, and not caring to not realize.
-I'll do anything for my "loved ones." I use quotes because my definition of love is something most people don't grasp. It's quite simple though. It's relentless.
There's a lot more. Maybe I'll continue if this has been helpful.