How to discern function order when typing someone?

I personally don't have too much trouble figuring out what function axes someone is on. Ti-Fe sticks out to me immediately as "this person does not think/process things the same way I do" – not necessarily in a bad way, just in an obvious way, whereas with Te-Fi people I can generally see their thought process even if I do not agree with them. Similarly with Si-Ne vs. Se-Ni, I find that it's pretty easy to tell based on the types of experiences somebody seeks out and what they find enjoyable about those experiences. Hard to describe but yeah, generally I can tell someone's function axes pretty quickly. The difficult part is determining function order.General questions: What cues do you use to determine someone's function order? Are there tipoffs that tell you what someone's dom or aux is?My specific situation, in case anyone feels like helping me figure it out (feel free to ignore): I'm definitely sure that my SO uses Te, Fi, Si, Ne in some order. It's not a case of "omg, we're soooo alike", because we're not, and Te is the only one that definitely isn't his dom, haha. But I feel like each of the others are equally plausible. Fi: has a very strong internal sense of how things "should" be morally, and gets very upset when people deviate from that. He'll often attempt to articulate what's "just the right thing to do" or "just wrong" based on his own conceptual understanding of the world. Thinks a lot, almost to the point of anxiety, about his own actions– for example, he values thinking before speaking, and one time he made a political facebook post that might have been somewhat impulsive. He then spent the next few days trying to figure out whether it was the right thing to do, concluded it wasn't, and then tried to figure out what led him to post it if he knew it wasn't the right thing to do. Ne: He loves finding patterns in data and looking at different interpretations of things. He's constantly trying to come up with the "meaning" of songs he likes, things he's observed, etc. He always gets super excited when he's doing something creative, whether it's improvising music or figuring out how to solve a rock-climbing problem, and he says the exciting part is seeing all the different possibilities. Si: Has a strong memory of his own past. Starts every day with Timehop (an app shows you your own social media posts from 1, 2, 3... years ago) and enjoys remembering each post in the context of what was going on in his life at the time. Very into music, but from an "Si-y" point of view. For example, he'll play me a Beatles song and then tell me about how it was written after John's mother died, focusing on what the music means over how it sounds. So yeah, Fi, Ne, Si all seem kind of plausible as a dominant function and I don't know how to decide between them. via /r/mbti http://ift.tt/2rwPDJF