The character approach is a bit strange. What I was trying to get at is that these functions, when paired with one of the attitudes, takes on characteristics of those attitudes. So the attributes normally ascribed to introversion: depth seeking, meticulous, quiet, reflective, inward-focused; the function actually takes on those characteristics and becomes introverted to an extent. That's why it's good to think about them as people; they behave like people do.
Another sign is that you feel disconnected from your body. Sensors do not do this. An intuitive preference is fairly unmistakable in this regard. Jung once wrote how he was once treating an intuitive who came into his room and said that she sensed that someone had been smoking, and the whole while there was a cigar in the ashtray literally right under her nose. Intuitives ignore sensory information in exchange for their abstract perceptions, thus they will be totally oblivious to the real world in some cirucmstances (if the intuitive process fails to provide them with the necessary information to make decisions based on the sensate world). Here's another example. I was sitting in class one day and the professor was lecturing from a PowerPoint. She turned to a new slide and I found myself staring at one particular bullet point on the slide. Eventually I deduced what the subject of this particular slide was from that bullet point, but then when I looked up I saw that the heading literally said what I had just been thinking, but I had been too stuck in my head to notice.
Anyway, at the risk of rambling too much, there are two other things that can confirm your Ni-dominance if you still have doubts. The first is, like I said earlier, that preferred intuition always means that sensation is repressed. If you struggle with focusing on details, if when you zone out you just tune out the sensory world entirely, if you forget you have a body from time to time or just normally don't think about your corporeal form, these are all qualities of inferior sensation. Basically if you struggle with sensory information in one way or another, that's a good indication.
The second way is a little bit trickier. I believe that I tried this in the other thread, but we'll see if it works here. The attitudinal opposite of your dominant function (Ne for you) is always the hardest function for a person to understand. If you have any ENxP friends, think about them. Ni-doms usually have a really hard time getting inside the heads of Ne-doms and following their trains of thought (Jung said something along the lines of 'seeing the wheels turning). I know I personally have a huge difficulty understanding Ne on more than a clinical level, and whenever I try to describe it to other people it is usually tainted by Ni influence. If this is you, then that can reinforce the Ni preference. A caveat, though, not understanding Ne shouldn't be definitive in your self-analysis; it is merely just a tool in reinforcing your type. If you have an easy time understanding Ne, maybe that means you should reconsider your type, but only if you have other grounds to do so. If, as we have seen here, you're pretty much the quintessential INFJ, then I wouldn't worry about it too much. I wrote these last two paragraphs mostly for your enlightenment, and to help you apply these concepts to your own life. If you're like the INFJs I know, you'll be typing other people. ;)