Hi Nana this is overall very good. You're a very advanced writer. Most of these corrections make your diction flow better, and make context more clear.

Toefl ibt writing (TOEFL usually spelled in all capitals)

These days, schools have a variety of teaching methods for their students. Some schools tend to teach them by providing them more job skills, whereas others focus on general subjects and their primary theories. In my point of view, I think it’s wise for schools to teach students about specific careers and jobs instead of general subjects. Obviously, there are a wide range of factors involved: 
To begin with, students become well-equipped with practical knowledge by teaching when they learn specific careers and job skills. This enables them to find jobs more easily after they graduate from school and they become well-prepared and far more confident when they take a job interview. This will certainly stand them out from other candidates.

Besides, schools can offer them a direct way to learn job experience, which without some people may find it hard to get when they start their work difficult. For instance, when my uncle graduated from school and began to work in a trade company based on his economic major. However, since he had never learned any career courses in at the university, he lacked plenty of job experiences, which made him in a bad situation of his job making his job situation a bad one. He could neither climb the career ladder nor get his salary rise. He ended up having to leave his job. [From which we can see how important job knowledge is when it comes to work.] This sentence is gramatically correct but isn't very useful when making an argument. If you wanted to include a sentence saying essentially, "See? This is the correct way to think," I'd phrase it something like: Based on his experience and the experiences of others like him, having previous job experience while in school is very important.

Last but not the least, learning this type of knowledge at school makes classes more practical and attractive, for many students would like to attend (this is already inferred). On the other hand, a class full of theories can be really dull, and students might not want to choose (choose works if you're talking about the specific class, otherwise use "concentrate" which invokes the subject and work itself) it next time. My university offers an optional course which relates to jobs and careers and there are always a large number of students attending the class; not only is the course essensial and useful, but it also teaches in a style of the professor's which is funny without a lot of theories.
Therefore, to teach students more specific careers and jobs paves a way for them to find their future success in jobs and is beneficial to both society and education.

Hey willywang this is good but I have a few suggestions for you:

A useful website

I visited a website called "TED" last month. http://www.ted.com/
There, I found are many interesting speeches and academic lectures. I have learned was able to learn some advanced knowledge in many kinds of area a number of advanced topics I had never really known touch before.

That is a tricky sentence. While what you wrote is understandable, there's some incorrectly used context and colloquial phrasing. 

Otherwise In addition, I believe I can improve my English listening and speaking of English skills can be improve by from these videos on TED. It is very I feel quite lucky that I to have found this website because the website it is very useful for me and other people who want to practice English.

Greeting for a event

I am asked to translate the opening remarks to a event. (Japanese →Ｅｎｇｌｉｓｈ）
Please check the remarks.

----------------------------------------------------------------------

Good afternoon, everyone.
I am XXX XXX, the director (museum curator )of Yokiso Villa. (yes, this looks good)

Thank you very much for participating in the International Exchange event today!
Before WW2, Yokiso welcomed many foreign students from other Asian countries. This made up an International community. The students who stayed here at Yokiso later contributed to strengthening straighten ties between their country and Japan our countries (it's clearer to be inclusive here).

We would like to pass continue the brilliant history of Yokiso by continuing its traditions (I understand your meaning behind this phrase, but you can word it a few different ways. This way makes sense to me but you might want to be more specific than my phrase "by continuing its traditions"...).
この輝かしい歴史を受け継ぎたいです。
( or We would like to take the role of Yokiso)

We would like to welcome all of you; many foreign students and foreign residents in Nagoya get together and enjoy the culture of other each other's countries. We believe the this event will help us to understand other people with different backgrounds.

Today, please try to talk with as many people from foreign countries as you can. We hope you will have new friends by the end of the event.
本日は、他の国々の人たちとお話いただき一人でも多くの外国の友達を作ってお帰りください。

Our event is not very long but we hope you will enjoy it and have a meaningful learning experience. Thank you.
それでは、短い時間ではありますが、十分にお楽しみください。

Very good writing. I have a few suggestions/corrections below:

Post-adolescence crisis.

Having finished high school [only] one semester ago, I've already started a new life. New city, new career and new friends. (adding "only" will help give context to "already", saying you've already begun a new life despite only finishing school a short time ago)

Living by myself these last six months was more scary than I thought it would be. I still can't believe that I already started my university life and the fact that I just left behind a part of my life full of memories and good moments.

Am I happy with that [decision]? (optional to add decision, but it will help make it clearer) It's hard to explain. It's a mix of emotions. Sometimes I feel happy for gaining some autonomy, for taking care of new responsabilities, but on the other hand I feel frightened and indecisive at the same time. (both "on the other hand" and "at the same time" are colloquialisms, as far as I know those sayings stay the same in every context that you use them) 

After all these changes in my life it's inevitable to that I will go deep on into my thoughts and ask myself about the future and why not the(??) my overall existence as well (I'm not sure if that's what you mean?). The truth is that I am not sure if I am making the right choices anymore. I am not sure what I want to do in the future, and even worst worse I am not sure if I like what I am doing right now.

Having a couple of friends who have already dropped their studies and don't have a clue as of what to do next makes me think even more. The only thing that I am sure these days is that if money wasn't a problem I would get away from this life as fast as I can, without doubting it for a second.

This is really good. It's a difficult, existential, philolosophical entry that makes use of a lot of complex sentence strucutres, not to mention abstract thoughts and conclusions. I say "hang in there!" your English is very good and you should keep working hard if you can. Do as great as you can in school and try to make it through, learning as much as you can. Good luck!

A lot of what you write here is gramatically correct, but doesn't flow very well. I'll try to make some suggestions below. Again, a lot of your writing is technically correct, but most of what I'm going to add will help make it flow better and, I hope, sound more accurate:

Easy Steps to Playing Guitar

Isn't it wonderful is to appreciate a well-played insturment? It is common to think that those talented musicians began practicing since they were pretty young, and that it is quite (perhaps you mean "only" here, as in it's "only possible to be good" I'm not sure) possible to be good at an instrument if a person begins playing since the childhood. If you hear a talented musician, it is very possible to believe that he or she had started to play since at an early age. But it is never too late to start a new instrument; for instance, look at how easy it is to start to play one of the most popular instruments: the guitar.

If you want to learn how to play the guitar, the first step of course is to buy one guitar. It is not necessary to buy an expensive one at first. A good clue is to start with a guitar with nylon strings. There are two reasons for that: For one it is way cheaper than the steel string guitars. And it is easier to play because the nylon strings are easier on the fingers, both for notes and for strumming chords. 

The second step that is recommended is to look for a good guitar instructor. It is essential to have a theoretical basis of the instrument. It is like someone traveling to a place that he or she does not know how to get to without a map. It is almost impossible to get to the destination without instructions. With an instructor, the new guitar student learns about the instrument itself, about musical styles, harmony and much more.

The last step is simple: practice! In fact it is not that simple, though it is extremely necessary. With guitar classes, the learner has exercises that are passed by the instructor. In addition a way of practicing that people use a lot nowadays is the Internet. It is possible to find and research chords and tabs from different artists and bands. And in playing the songs that he or she likes, it becomes an important impetus for learning the instrument.

Here are the first steps again: Get a guitar, to look for a good instructor and to practice. Naturally the more the learner improves on the instrument the more steps he or she will find. Learning a new instrument is a wonderful experience, and it is never too late to do it.

I agree with Ryan. English is a very difficult language to master. I think there are tougher languages to learn, at least in regards to western languages. When I lived in Austria most Austrians thought German was the hardest language to learn (even though it was their native language). I suppose it depends on context and how much you want to master the language.

But yes, the metaphors, colloquialisms and idioms are difficult and sometimes outright bizarre. And we English speakers use them all the time. But the basics I believe are easier than some might lead to believe.

This is really good, Ayu. Just a few suggestions:

Why I couldnt have a good sleep? (This is actually a statement, not a question ? -- you could ask "Why couldn't I have a good sleep?" or "Why I couldn't have a good sleep." Flipping the "why" will change question to statement in this case)

Today I was so lazy. (don't forget spaces after periods and commas . , ) I woke up at 1 pm in this afternoon since I went to bed at 3 am last night.
Usually when I go to a pub or club after that I can't have get a good rest that night.
I guess it's because of my brain still can't stop working and it stays still being a bit excited (this is just about right, but it's not quite accurate in this context. it would be better to say): continues to be active.
Anyway I wanted to go out since the weather was not really bad (simply saying "nice" instead of "not really bad" also works), however I felt like to do doing nothing so I just stayed home.
So it's a lazy Sunday for me~. But on the other hand, being lazy is not that bad