Test results, even the MBTI, can be inconsistent. At the same time, the breakdown of preferences that is typically done in the verification can be misleading, since other preferences can influence expression of type. N and S especially can color both the manifestation of T/F and J/P.
Jungian analyst John Giannini suggests approaching type by looking at the information gathering and judging functions, that is, looking at it in terms of ST, SF, NT and NF. This makes more sense to me than Keirsey's division, which in many ways seems arbitrary as it divides by information gathering and judging functions for the intuitive preference but information gathering and outer-world behavior for the sensing preference. Giannini's suggestion has the advantage of consistency, as well as partially corresponding to the way Jung divided the functions.
Assuming that the person knows either their information gathering or judging function, you could begin by looking at which you're sure of, and see which of the pairs fits better. For example, if you know you're an N but not an F or T, then you might look at NF and NT to see which is the better fit. If you were to be torn between S and N, but know you're a T, you would look to see whether SF or NF sounded more like you. You would then narrow it down by determining which function is your Achilles' Heel. So, for example, if you figured out you were an NF by the above method, you need to figure out then if Sensing or Thinking is your weak spot. This would be the area you have the most trouble, but also the area where you're most easily influenced and the area where you're most sensitive to being criticized. If, for example, you determine from this process that your weak area is Thinking (e.g. the inferior function) then you know you have to be a Feeling type. That would mean that you would either be an INFP or ENFJ. Now all you need to know is either E/I or J/P. If you don't know whether you prefer introversion or extraversion, you can at least determine whether your outer world behavior is done in a judging or perceiving way. So, if you know that you're a J, you know you're ENFJ, even if you aren't sure about whether you're an introvert or extravert. On the other hand, if you know you're, say, an introvert but don't know if you prefer J or P, since you already know you're a dominant feeling type, you know you're an INFP.
The hardest part to this three step system is the second part: knowing the inferior function. Some questions you may want to ask yourself:
(1)What areas are the hardest for you to take criticism? This is valid for both thinking and feeling types, as everyone gets touchy around the inferior function. For example, INTPs can handle all sorts of criticism of their intellectual work but can become extremely touchy when someone indicates that they've fumbled with feeling stuff.
(2)What areas are the most intense for you? Often we feel more alive when we engage the inferior function, precisely because it's neglected so much of the time. For example, some sensing types will have a powerful dream and become convinced that it is a premonition, but this is in stark contrast to an otherwise grounded, present-focused, what-you-can-see-and-touch point of view.
(3)In what area do you really want to do something, but just find that you quickly fall back on the opposite function? A Feeling dominant may find themselves drawn to an area that requires logic and analysis, but quickly become uncomfortable with how their weakest area is exposed and then withdraw from it. This does not mean that a certain type won't try certain majors or jobs. While it can manifest as avoidance, it can equally manifest as finding a way to approach the thing in a way where they can fall back on their dominant function. Take, for example, the discipline of philosophy. This is a fairly NT-discipline in many respects. Jung described Kant as an exemplar for introverted thinking. Now, an ENFJ may undertake serious study and even have an interest in Kant's epistemology, but after a short time in graduate school may decide to pursue an area more in line with her dominant function--for example, environmental ethics. It takes tremendous courage and perseverance, as well as a very modest ego, to trudge through in the face of our inferior function. We may try, but we habitually try to do inferior function related activities through our dominant function. A dominant intuitive may love painting, but find they just can't seem to hold their attention when asked to render a bowl of fruit exactly as it appears to them--although they may be an excellent abstract painter.
Next up: description of the couplings.
