If you want to be a good writer, then be a good reader. (Also, if you want to be a good speaker, then be a good listener.) By reading a lot in English, you will be exposed to many different models for writing.
Read poetry if you want to write like a poet. Read entertainment magazines if you want to write about music and fashion. Read business newspapers and journals if you want to write like a businessperson. That way you can learn the style and vocabulary you need to be a good writer.
Keep a daily journal. Write down what you did that day. Write down interesting expressions you heard. Write down new words you learned with example sentences.