1. Capitalize the first word in every sentence - Hello, not hello
2. Always capitalize I - I, not i
3. Always capitalize English - English, not english
4. Do not put a space before a period, put a space after a period - It is a nice day. Not, it is a nice day .
You say that you have a good command of reading. Pay attention to what you are reading. Notice how the writer uses the language. Some people who want to become better writers will copy what other writers have written. Sit down and either print (with a pen or pencil) or type a page from a book or article that you have read. Do this every day. Also, when you are reading something, read it out loud.
Student or Learner