I'll chime in with my input.
First, N vs S:
Intuition is about patterns and relationships (between patterns and entities).
Sensing is about specific entities.
Intuition is a model that we have in our heads. It doesn't necessarily match reality, though it is likely. The model fluctuates, as we realize how close to or far from reality we are. Intuition is often largely based on reality, but it resides in our minds.
Sensing is, for lack of a better word, being more "present" and grounded in reality. Of course there is information in our heads, but Sensors generally don't "add to it" in the way intuitives do.
Now for the specifics:
Se is, in my opinion, the "very present" perceiving function. Real time information is perceived immediately that one may react promptly. Some would argue that this is the "most used" function regardless of type, simply by definition, even if it isn't preferred. I personally believe that in a Jungian sense, we're more concerned with whether Se is preferred, not whether it is simply "used." The preference for Se means "living in the now" is important to oneself.
Si is, loosely speaking, how much one relies upon one's memory. It does not imply that one has a good memory, though there may be some correlation. I've noted Si users to misremember things and be utterly certain of that incorrect memory. The preference for Si means that one regards one's memories as being reliable, correct and a proper choice for guidance with respect to making decisions. Contrary to popular opinion, Si users are not averse to new ideas, but it takes time, just the same as it takes time for Fi to get used to a new feeling, or Ti to accept new logic that one didn't derive oneself, or Ni to fully understand a new pattern. Also, when I speak of N being about patterns and S as being about specific entities, S can recognize patterns and use them, but it doesn't "think in patterns" so to speak. For Si, a pattern is a feature, an entity, of reality. It doesn't "switch out patterns" the way Ni does.
Ne is remarkably similar to Se, in that it relies on external, real time data. However, upon perceiving something in real time, the mind then jumps in and starts relating what is seen with everything else in one's mind. So one can express a fascination with what one is sensing, but the real fascination is with the mental stimulation that is provided.
Ni, my dominant function, is more like Si, and more like a memory. It is not, however, a memory of specific entities or specific patterns, but a memory of kinds of things. So upon observing something or judging something (with Se or Fe or Te), Ni starts correlating the observed/judged thing with memorized patterns. This is where the spooky insights that Ni provides come from. Pattern matching looks things up in ways that most people don't "see", and thus the patterns point out things in a really obvious way to the Ni user that are not obvious to others.