How can I improve my English skill?

You are doing pretty good so far. Excellent use of punctuation and capitalization. There are several people on here from India, the Philippines and other Asian countries. Many MyLotters from Asia have commented on how MyLot has helped them improve their English. My first piece of advice to you then is to be as active as possible on myLot. Participating in a community of over 200,000 members that uses English in every conversation does wonders for one's English skills. I suppose you could say it rubs off on you. I am a native English speaker and yet find myself improving my own English by just being here. Furthermore, I would suggest that you sign up for something called "the word of the day" that most online English dictionaries have. They email you one word a day. It is a great way to add to your English vocabulary. I have done this myself and it is quite effective. Finally, there is a website called learnenglish.de (www.learnenglish.de). It is free and I think it would be of use to you. I am a writer and this website has an excellent section on describing things. However it is possible that the entire site might be of use to you. :)

Read! Get good books (I like George Orwell), they will have good english in them. If not, then get a penpal! Someone who wants to learn Vietnamese and with whom you can trade English. =) Or download english learning books.

Read a news paper daily. Converse in English with your friends without feeling shy. Hear and see BBC, CNN news channels.[b][/b]

thats good feeling and for you the best is to read news papers and articles specially related to your interest

Search from the net basic English grammar. Keep using English while at home. Always do free writing, soon your English will be better if you keep talking in English.

Hey there. I'm also originally from Asia (now residing in Canada) and one advice I can give you is to watch a lot of movies and read a lot of books--it doesn't even matter what genre. My first year in Canada, all my professors in University were surprised to learn that I was an immigrant with no prior experience in speaking English full time, my accent was barely noticeable and my use of the language too smooth for what you might call a beginner. When they used to ask me how I learned I would always tell them the same thing I'm going to tell you. For me the best (and most fun) way to learn casual/conversational English is to watch a lot of movies and sitcoms. Comedies, romantic comedies, nothing too serious. This way you learn how people who speak English actually use the language in normal conversation and I think it's best you learn that first before you get to the heavier/formal usage. Also read light news and contemporary novels because that will help you a lot in simple sentence construction. Back in school when I was younger my English teachers were crap. Believe me, they were so bad I sometimes felt the urge to go to the Department of Education and complain about them, consequences be damned. Anyway, the point is simply by immersing myself in material in the English language I learned it almost unconsciously. It's also more fun and infinitely less boring than going to formal classes don't you think?