Hi. I'm 16-years-old, and over the past couple of years, I've had a lot of trouble. I won't go into detail, but basically, I'm underachieving (despite an IQ in the top 1%), I have literally no social life, and I've been kicked out of school. I'm an ENTJ with enneagram 368 (not sure on the order), so this is literally a living hell. It especially annoys me, as I always saw ENTJ as a really cool type; the natural leader that everyone depends on in a crisis, but I'm just an unsuccessful bully.
My problem is my Te and Ni work in an unhealthy way. Instead of my Te organizing the environment to accommodate Ni long-range vision, my Te works as a tool to logically justify my Ni paranoia. This makes me swing from being extremely self critical to downright narcissistic. I also have unusually good Fe (which made me think i was an ENTP or ENFJ), but that just gives me social anxiety. Does anyone know how you can develop Te and Ni to be healthy? How do you improve as an ENTJ in general? Advice from anyone welcome, but particularly want to hear from ENTJs. Also, ask me any questions you need to, I'll answer them as best as I can.
Cognitive Functions: Te>Ni>Si=Fe>Ti>Ne>Se>Fi
Now that you've got ENTP instead of ENTJ, and social anxiety...
Short version:
You might just be introverted, but not pushing yourself into socialization enough to realize it, if your anxiety leads to your avoidance of others. It's really, really difficult for me to realize I need to socialize a bit until I actually do it sometimes, but not enough socialization has caused me to mistype as extroverted in the past.
Long Version:
I know your search is likely a bit more broad than this, but what ultimately helped me in the differentiation between ENTP and INTP (besides the practitioner discussing w/ me, which helped tremendously so I have to credit this)...if you spend a lot of time in solitude, get out and socialize to make sure you're not just an introvert failing to recognize the need for more human interaction due to breaching your own subjective balance threshold. Everyone is an ambivert, but if you're energized by interacting long term, you're (X)e Dom function, if you're drained after long term, you're (X)i Dom function. Note: you can still be an introvert and energized by it if you were in shortage of it. That's happened to me before. Gotta push yourself past a threshold...like between work and social gatherings 6 days a week, that's my threshold. I can't handle that schedule. The dominant function is only going to be whatever you are socially bc you will want to spend the most time in your own dominant function. It's really, really difficult for me to realize I need to socialize a bit until I actually do it sometimes, but not enough socialization has caused me to mistype as extroverted in the past. If I tried to spend the same amount of time interacting with others as I can in solitude, I would lose my mind and be on edge. It's easy to tell when I need space, not so easy to tell when I need interaction. That's part of what makes me so certain. I spend a few days 100% alone and I'm great...I spend a few hours around a lot of noise, chaos, and activity, and I feel like I'm going to erupt like a volcano. My friend knows when I'm at my threshold because I get really quiet and tense. Maybe this would help you if you're struggling with the I/E Dom Function determination.
EDIT:
I just remembered that my dad is an extrovert, but still needs to just get away sometimes. So perhaps my thoughts above are premature...but personally, I have the ability to seem like an extrovert with customers (situation in which I am forced to interact), but eventually I just run out of the fuel to do it and I get quiet because I just can't anymore. I burn out. My Dad seems to be able to actually maintain it, and seeks it out on his own. It's not mostly situations where it's forced, he creates the situation. I don't really do that much. In fact, just take all of this with a grain of salt as these are just current understandings and subject to possible change and growth after further exploration.
The rest of this was not part of the edit:
Ti/Ne:
- Other people tend to arrive at conclusions faster than I do. I tend to encourage people to slow down and consider more options.
- Would rather take some time to consider my options before making a decision.
- I tend to take a cautious approach to conclusions compared to others I've known.
- I hate feeling pressured to make decisions about unfamiliar things immediately.
- Holistic (Explodes like a huge mind map, sometimes overwhelming. Rather have one ultimate end-all be-all decision than make a mistake or a wrong move. Effective in accuracy. Sees so many options, can sometimes struggle to narrow them down.)
Te/Ni:
- Something I like about myself is my decisiveness. I like to make a decision and keep moving forward, even though I might have to refine it later.
- Would rather make a decision and not get caught up in paralysis or hesitation. Not necessarily careless about mistakes, but will correct as I see a need for improvement.
- At times I can be tempted to to become impatient when people take too long to decide.
- I think it's more important to keep moving forward than to get everything to be perfect in the first try.
- Linear (Decide and Move Forward, even if it's not necessarily the ultimate end-all be-all decision. Efficiency in terms of progress.)
PS
Set goals for yourself now. My IQ score / aptitude / opportunity was up there too, and I didn't apply myself in school. Living this life I live now is a whole lot harder than it would have been to just discipline myself to do school and not care about the acceptance of my hateful peers that I don't even talk to anymore 10 years later. Everybody hates the smart kid, but it's better to be hated for a season than to hate the rest of your own life because you tossed it aside and procrastinated to try to gain their acceptance. Where you start is not as important as where you end. So quit getting kicked out of school and go far. 
Maybe that's not even your situation and I'm projecting bc you remind me of myself, but...I'll say it anyways, because then again, maybe I'm not that far off from you, too.
