I spend a lot of time around them before I try to make a judgement. It's trial and error and research on the cognitive functions. Also, I see how they relate to me(I can tell an Ne user pretty quickly since I share it in common). I decide if they're introverted or extraverted, and I entertain different types until I can narrow it down to a few choices.
Look at the traits of their extraversion, then see what colors it. ESTPs are extraverted people-persons that seem superficially nice and relatable(tertiary Fe). They have a serious, logical Ti mode, and you realize that this is what happens beneath the surface all the time. The T game is stronger than the F game. Similarly, in ESFPs, they speak in a way that is colored by Te, but you can see the Fi under the surface. It's a little bit harder to do this with introverts because you'll normally see that second extraverted function when they are stressed out. But by what the extraverted function does say, you can tell if they prefer N or S.
The more I know about how I am, the more skilled I am with determining someone's type. I'm still trying to learn how to type people by their writing.
Look at the traits of their extraversion, then see what colors it. ESTPs are extraverted people-persons that seem superficially nice and relatable(tertiary Fe). They have a serious, logical Ti mode, and you realize that this is what happens beneath the surface all the time. The T game is stronger than the F game. Similarly, in ESFPs, they speak in a way that is colored by Te, but you can see the Fi under the surface. It's a little bit harder to do this with introverts because you'll normally see that second extraverted function when they are stressed out. But by what the extraverted function does say, you can tell if they prefer N or S.
The more I know about how I am, the more skilled I am with determining someone's type. I'm still trying to learn how to type people by their writing.