How to improve English Writing Skill? Tips please!

Ah, now you’ve got a more specific question. If you’re concerned with style, I assume that you should have almost no problems with background knowledge such as grammar and writing units and structure (phrase – clause – sentence – paragraph – essay). Writing styles is not only about the language but also a personal identity, but for the purpose of convenience (especially when it comes to spelling check in MicrosoftWord hehe) American English is a better choice. Here are some suggestions appropriate for Vietnamese learners I guess.
1. The distinction between American and British English is broad itself, regarding vocabulary (dialect) and form more than grammar. You can have a handbook of American English for reference. Spelling is one of the keys. Some examples for real (British – American): learnt –learned; got-gotten; programme-program; labour-labor; organise- organize, etc. Different forms for a same meaning set another issue, for instance: lift-elevator; sweets-candies; toilet-rest room; invigilator-proctor, etc. As a matter of fact, its not so important what type you go for, what matters is whether you’re consistent. If you switch between the two in one writing, you’ll be considered as unprofessional and non-academic.
2. Bear in mind that English is ways different from Vietnamese. So try not to translate when writing. Though you may find the idea of expression similar, it doesn’t mean you can just transfer word to word. This is one of the most popular AND principal errors most of my students make in their writings. For example, Vietnamese tends to use a lot of verbs (let alone no forms), whereas English is a Noun-Oriented language, which implies the key meaning words in a sentence are supposed to be nouns. Verbs function more grammatically than lexically – and they’re often common verbs. So instead of saying (normally) ‘I decided’, they’d say ‘I made a decision’.
3. Form a habit of using passive voice, particularly when the ‘who’ is not important in the message – or inappropriate. When you write something like ‘The government should introduce a new tax policy’ you’re actually putting yourself …higher than the government! But not all realise this when they write. Be more modest, sensible and neutral! Instead, just write ‘A new tax policy needs to be introduced.’
4. Which one do you choose? ‘I feel that I lack of knowledge of expressing myself with sophisticated English’ or ‘I lack the knowledge to express myself in sophisticated English?’ A native speaker will use the second! English is very idiomatic. So learn idioms and collocations as many as you can. Simply because idiomatic English is not based on any rules, but rather on usage. Therefore, the degree to which you master idiomatic English depends on the exposure you have. Five concrete tips for improving your command of idiomatic writing are as follows. (a) Read in English, (b) Listen attentively to the way English is used, (c) Think in English, (d) Interact with native speakers and (e) have your writing proofread.
5. Pay attention to word order/position and word choice, especially adverbs. For example, we tend to inform the reader adverbs if time at the beginning of the sentence while in English we need to reverse this order. So instead of writing ‘Yesterday I saw a beautiful girl’, change the order to ‘I saw a beautiful girl yesterday.’ Other adverbs of manner usually have their best effect right after the subject, for instance, ‘He purposefully put the vase on the table.’
6. Diversify your ways of expressing. It’s like cooking the same dish different ways. So that you don’t get bored with yourself! This helps a great deal when the idea is repeated in one writing.
7. Be very specific and go straight to the point. Cut down on unnecessary words. A Vietnamese typically writes ‘Too much noise makes people have headache’, while this could be better expressed as ‘Too much noise causes headache to people’: obviously one verb is simpler than two!
8. Attend an intensive Writing class if needed.
9. … and last one: Practice makes perfect.
Wish you success.