First, read a considerable amount of English writing by a range of authors in a variety of different settings. There is no singular “excellent style”. Crisp, clean sentences that work well in a newspaper may seem choppy if contained within the body of a novel or other work. Similarly, detailed descriptive phrases may be out of place in a magazine sidebar designed to cut to the facts of an idea or concept. Secondly, study some textbooks. English can be complicated due to the irregular tenses of some verbs and words that sound alike but have dissimilar meanings. Pay attention to the basics, like capitalization and punctuation. Finally – practice! Very few skills are natural. Most are acquired. Start by writing short paragraphs and sharing them with your friends for review. Take their serious comments under consideration, but remember that even the most popular writers are not universally loved. Develop your own style and go with it.

Read English storybooks/novels. Try writing a character sketch of one of the charcters in a book – or a review. OR rewrite the story/summary in your own words.

Get back to basics. First of all, study grammar, spelling, etc. Read a lot of books, not very difficult ones.

Be very dramatic when writing, make your sentences long (but not run-on sentences), and use a variety of large vocabulary.

read a lot of books, pay attention to how other people write their book and learn from it..

Practice, practice, practice. Get feedback.