What is the best way to learning another language?

Consider rewriting as: What is the best way to learn another language?
Also, usually a title has the first letter of most of its words as a capital letter. However, I think your title looks OK here!

What is the best way to learning another language?

See section above.

As far as I know, it is not easy to explain.

How to study is not important, how to schedule is more worthy.

How to study is not as important as how to schedule your study.

Official reports and questions ofabout exams tend to use difficult terms and topics.

To make sure to say that I'm not familiar with politics.

I don't quite understand what this means here.

Learning vocabulary, grammar and, pronunciation.

This is not a valid sentence.
Consider what you have written here as a follow-on from what you have written above:
"You are supposed to study many things before you take an exam, such as vocabulary, grammar and pronunciation."
Note, that you don't need a comma (,) between "and" and "pronunciation".

You have to get the skills to understand things that you read a sentence in a second.

"You have to get enough skills so that you can read and understand a sentence in a second."
Instead of saying "get", you could use the word "acquire". Look up "acquire" in the dictionary.

How can I get a skills like that?

A time that you have to learn is not a little time.

"The time that you have for learning is not insignificant."

I can say that a great foreign language learner is a person who is also a great scheduler.

They are so to be flexible and to be strict.

"They can be either flexible or strict in their studying, depending on their learning needs."