I learned English fromas a junior high school student.

By saying "from a junior high school student," you are saying you were taught English by a student, while saying "as a student" says that you learned English while you were a student.

It's been almost 10 years!

Therefore, I'm good at writting and listening.

My big dream is to work ing a foreign country.

So, I should study English harder to achieve my goal!

If you have any idea to achieve my dream, please tell me the helpful advisesshare your advice with me.

I learned English fromin junior high school student.

or "I learned English when I was a junior high school student"

It's been almost 10 years!

Therefore I'm good at writting and listening.

But my English speaking ability doehasn't improved.

My big dream is to work ing a foreign country.

I want to speak English fluently at the businesswork.

So, I should study English harder to achieve my goal!

If you have any ideas on how to achieve my dream, please tell me the helpful advises.

I've been learneding English fromsince I was a junior high school student.

Since you learning English is something that started in the past and is still continuing to the present, "I've been learning" (what we call the present perfect) is expected here.

It's been almost 10 years!

"Been" implies that you're counting from the time you were a junior high school student.

Therefore I'm good at writting and listening.

But my English speaking ability doehasn't improved.

"Hasn't" is in what we call the present perfect tense. It's used when we're referring to a past event that still has consequences in the present. The past event here is your English speaking ability not improving. The present consequence is that you're still not good at speaking English.

My big dream is to work ing a foreign country.

"My big dream is working in a foreign country" is understandable, but I think "My big dream is to work in a foreign country" is the more natural expression.

I want to speak English fluently at the businessmy job.

Alternatively, and depending on what you meant by "business": "I want to speak English fluently when doing business."

So, I should study English harder to achieve my goal!

If you have any idea to(s) about how I can achieve my dream, please tell me thsome helpful advisesce.

(1) I rewrote the first half of the sentence to make it sound more fluent. Do take some time to look over the changes.
(2) "Advises" is a verb. (The third-person singular form of "advise", to be specific.) "Advice" is a noun, and it's an uncountable noun, so we do not say "advices".
(3) Alternatively: "please give me some helpful advice."

I lestarnted English fromin junior high school as a student.

It's almost been10 years so far!

But my English speaking ability doehasn't improved.

My big dream is to work ing a foreign country.

I want'd like to speak English fluently at thein business. settings

So, I shouldneed to study English harder to achive my goal!

If you have any idea tohow I can achieve my dream, please tell me the helpfuladvise me/give me tips.¶
Or just¶
Please give me useful/good advises.ce!