how to improve written english..?

Answer 1

Try reading this:
http://andromeda.rutgers.edu/~jlynch/Writing/

Answer 2

Listen to people on Yahoo! answers criticize you for not saying, "How do I improve my written English?" Part of learning to write well is learning to read well. If you don't want to write like a scholar, and just want to improve your writing to the average standard of most English speakers, a great place to go is the newspapers. Read articles from the New York Times or the Washington Post. It will improve your English and in addition you will get a better perspective on American culture. Obviously, you could take classes as well, but I assume you are already doing so. Reading complex grammar books helps with the syntax. Another part of writing well is practice. Getting an English speaking e-mail pal to correct your writing is a good start if you don't have the money for a private tutor (and who does?)

Answer 3

Get a pen pal fluent in English.

Answer 4

Read a newspaper every day. That is actually a proven method taught in many schools.

Answer 5

Read Strunk and White's "Elements Of Style" then practice