There are 5 components that contribute to typing people well;
1) An intimate and comprehensive understanding of the type theory that is being used [theory],
2) A degree of familiarity with the individual, enough to draw lines between type theory and the typed individual,
3) The ability to tie these pieces of observations together and form thorough conclusions, taking into account possibilities of how human behaviour manifests [practice],
4) The ability to actually then explain one's observations,
5) The ability and willingness to adjust for new information if they come. Barely anyone gets typed on round 1.
In my opinion, you don't have to be right, but you do have to be able to explain what you're saying. The right (or most accurate, best fit) answer will come then. A human being is a ball of moving bits of information that can't just be dissected under a lamp. I doubt any of us strikes all 5 at any given typing attempt, but this is food for thought for those wondering how well they type.
Some folks know people really well, but have no idea how to explain them typologically. Some people are encyclopedias of type theory, but have no idea how to apply it to observe people and draw conclusions. Some folks have both, but lack the ability the explain, it's a 'gut feeling' that would crystallize with words, except the words don't quite come. Or, they are observing the right thing, but mis-applying type due to a lack of understanding of the types in depth, but revisiting and re-assessing things later on once they have better understanding (or just giving up).
Real answer to the thread: I don't think about how good I am (and thus do not and won't rate myself), but I do try to be aware of these things.
Due to the issues listed, and other factors I'll discuss below, I feel like often typing others is of limited value. I have noticed that often it is used as a weapon (I hate X...You display the characteristics of X - wait, did I SAY I didn't like you? I'm merely calling types as I see them), or people feel offended when they think they are being mistyped or given an unflattering profile or one that doesn't match how they experience themselves.
I maybe have generalized categories for people, but mostly have found typology of any kind useful for understanding why I might understand the world differently than someone else, and also for helping me figure out some of my potential areas to shore up or strong things to capitalize on. I've learned some useful things on here about why certain types hitch well, or push one another's buttons, and I've also learned through discussions in the earlier days of this site where we might get snarled up, and not understand one another, even if we are speaking the same language. That was eye opening to me at the time, as you rarely get into the same kinds of discussions in real life, nor do you get into it with people that also want to figure out what happened.
As with most other areas of life, when people are most certain that they are great at typing people, that's usually when they have more to learn. There are so many different variables that influence how personality gets expressed: upbringing, trauma, mental illness, religious bent, size of family, profession, opportunities, life experiences, location, culture, language, age, etc. Also, being too close to someone or too distant will influence how you perceive them. People interact differently with different people in their world. Someone who is normally unemotional may be uncharacteristically open with one person, but seem very closed off or distant to others. Someone who is normally very open about themselves may have a private side that you only understand is there once you become better acquainted with them. The way the relationship between yourself and someone else is established influences interactions too. Often people kind of fit into certain roles in one relationship, which may be different from what is expected in other ones and therefore make the person appear somewhat different, depending on whom they are interacting with.
Because of all these considerations, the longer I've looked at any typology system, the more I've concluded that it may be interesting to see different ways people have observed and categorized types of people in the world, but each system is only a tool, and an imperfect one at best. Having said all that, I recognize that there are certain people that are much quicker at sizing up and describing what they are looking at when they meet someone new, in a way that I can't. I do think that's related to them have stronger functions in some areas where mine are weak or almost non-existent. There are there are other ways of evaluation that I once assumed were universally apparent, which I've since found that only me and similarly wired people seem to readily see, so it wouldn't be impossible to me to assume that some of you are better at typing people than others. Perhaps part of the reason that I don't find it as interesting is because it is not a skillset that I'm naturally proficient with.
