From my experience, Beta types have a distinct look (similar to the above) characterized by an earthy, often sensual, and cunning aura. Even in those that are a little socially inept, there's a latent smoothtalker underneath. They have a gravity around which manifests in more methodical movements, coordinated presentation, walk and facial expressions. They can display quite a contrast to the Alpha types who are less smooth and more silly and spontaneous.
What makes up this appearance is two parts. Their eyes (which are serious, focused, and a little hypnotic) and their smile (which is well toned, forward and coordinated). Here are images of what these look like:
When Ni is strongly represented, the eyes are unfocused, but still serious. The skin around the eyes is stretched away from the eye, but the top of the eye is partially covered by the eyelid. They may look unimpressed, bored or generally relaxed. Their eyes may also drift to the sides and "zone-out" (bottom images) as they access their Ni's worldview.
The second part of this is their mouth, which is hard to define without comparing it to the Te/Fi mouth. But generally speaking, there's a "toning" of the zygomaticus muscles that run horizontally from the ears to the corners of the lips like so (the arrows):
This tone makes their mouth look a little "confrontational" and forward even when at rest. The lips are pursed a little bit, with the outer edges of the lips slightly lowered. They may look "upset" and condescending. But when they smile, it's via a nice, smooth smile that opens up from ear to ear and creates natural dimples as the skin is pushed out of the way of the smile like a theater curtain being opened.
So what do you guys think? How would you rate the accuracy of this method?