incorrect writing

Output is important for learning a language, I mean writing here, a problem is how to make sure your writing is correct by yourself without a language environment? No tutor, no teacher, no classmate, just you.

I think the answer is in the input, through massive reading, you will notice that you have ever written something wrong and correct in the future, therefore, to write better, you should simultaneously read massive original version, the progress will ensure and remind you that wrong expression written.

This will happen automatically, don't worry, you just keep reading, writing, reading, writing... Practice makes perfect! that is all, no big deal.