If a function is beginning to confuse you, please refer to this list in order to snap yourself out of it.
Ni: Introverted Intuition. Ni is about introverted intuition. Introverted: gaining power from your self, pre-occupied with your own thoughts and feelings... and combined with intuition, instinct etc...it's about self-analyizations and exploring inner worlds and your hunches. Since one can only find meaning in the world by looking inside one self, it's about deeper meanings too. Ni is never about what is right/wrong, but about what is meaningful. Ni also understands (though not necessarily effects or directs) the 'inner workings' (what makes something tick in and of itself, regardless of what people say SHOULD or DOES happen) of phenomenon quite naturally.
Ne: Extroverted Intuition: Ne is about projecting and understanding the intuition/inner worlds of everybody in the world. It's about combining and balancing what multiple people (extroversion- gaining energy from others) think about a given subject. That's why ENFps have a tendency to be so diplomatic, docile and "Politically correct" when it comes to all the issues we face in the world. They can't help this, that's just how Ne is manifested.
Se: Extroverted Sensing: This one is a bit tricky (and is technically the most poorly-named function in the socion, semantically speaking) for a lot of people to understand since, inherently all functions are psychological. So psychological in fact, it's hard to ever accurately describe a function in words as even in writing I am externalizing things. You can't really think of extroverted sensing as some tactile purely 'physical/corporeal' process of basic touch even if that's tempting to do so. When looked at psychologically, all extroverted sensing really translates to is one's own psychological *will-power* and also psychologically sensing the will-power in others. That's why Se-egos act quickly and with so much self-confidence.
Si: Introverted Sensing: Describes how well you yourself, psychologically (which in ways gets translated to physical manifestations) respond to the comfort in *everything* in the universe. Extreme, but ultimately true- as one really can't dilute what Si *purely* is in any way. Not just 'how good the room looks', but also how sharp or soft people are being in their psychological communications etc. (Fe is sometimes confused with Si, but as you know from my behavior here I rarely care about the comfort of others as much as I worry about the emotional impact.)
Fe: Extroverted feeling: Extroversion (getting energy from others) and feelings, well you know what those are. So Fe is about getting energy from the feeling of others. It's really that simple. People with 'good Fe' get energy from how other people are feeling. They want people to feel okay because they get psychological energy from that. They want to obey certain rules of etiquette and social norms, not because they're trying to be too 'politically correct' and annoying, or 'Too Fake' but because they themselves are empowered if they can direct the mood of a situation. I kinda said the same thing three times, but that's another example of my Fe manifesting. Fe is about obvious emphasis. But it doesn't naturally embellish something so much as to not make it true any more.
Fi: Introverted feeling: Okay see the pattern here. Introversion, gaining energy from your self....and feelings...again, you know what those are. So Fi is about getting energy from your own feelings. Which translates to how much you like or hate a certain object. It also gives you an awareness of what is important to other people, which can be similar to Ni/Se but more erm 'relationship-orientated' and more naturally objective.
Te: Te is about psychologically projecting and understanding what is objectively and purely true. Not what you yourself think of facts- or even your personal viewpoint AT ALL, but basically what something purely objectively *is.* That's why Te is so business-like. Te-egos easily synthesize and construct all mental information from outside sources, being easily able to smooth out any 'junk' or subjective filters that would get in the way of directly expressing the situation and exposing everything for what it is. That's not to say that Te is like anti-emotion or anything, just that because of the inherent know-how at externally categorizing intelligence- it easily appears that way. ESTjs and ENTjs' own subjective feelings about Te (and lots of other things) can be very strong, passionate and romantic, but psychologically, as the function itself -- that's not what it is about.
Ti: Ti is about raw, pure intelligence basically. How 'raw-ly' smart you are, how easily you can mentally categorize and compartmentalize information (like all intelligent people do), such as professors/educators. (Not necessarily paying any privy to the expression or externalization thereof, which is Te) Yes everybody is smart in their own way and even Ti-egos will do stupid shit. But Ti as a function describes inner, innate intelligence....kind of the building block (reality tunnels) in the mind. As such it also connects the other functions together in the mind, naturally. Ti is the glue, and the reason why Ti-egos are so misunderstood/socially awkward, is exactly because of this. It's basically smartness in a vacuum. When looked at Ti directly, it isn't sexy nor does it try to be. But it serves as the inner urge in us all that makes us think about everything we're doing.