Gwyn G.B.
It may sound trite, but just write. You need a lot of practice and the more writing you do the better you will get. Get feedback on what you do write and read lots of good books so that you can learn from the best.
More Answered Questions
About Goodreads Q&A
Ask and answer questions about books!
You can pose questions to the Goodreads community with Reader Q&A, or ask your favorite author a question with Ask the Author.
See Featured Authors Answering Questions
Learn more