Read widely it will help develop your style naturally. Human knowledge is continually expanding and no one person, however learned, can possibly know everything. In fact, outside his own narrow specialist field the most eminent professor may be sadly lacking in knowledge of the world.
To read other works will help you to have some knowledge of the classics of the English and other major languages but you should not confine yourself to Shakespeare, Dickens, Milton etc. You should try to have a knowledge of modern authors and also the work of newspaper and periodical journalists.
Obviously you should read the type of books you enjoy as this is probably what you will aim for yourself and you will need to steep yourself in the category. However, if you would like to see how a variety of others write and try to work out why they have had their work published then do not consider time spent browsing in one of the larger bookshops as wasted.
Shops have more up-to-date books than libraries can afford – books mentioned on TV, books that have been nominated for prizes. There are often free copies of magazines that review books. You need not to buy many but it will give you ideas and you can then order books which have caught your interest from the library. Even if your local library does not have a copy it will obtain one for you to read if at all possible.
Also, look through newspapers and read their book review pages. Again, make a note of what interests you. This does not apply only to those who write fiction but it can be useful to writers of non-fiction too. The work of others should be read and digested not just to gain knowledge.
You should also study the writer’s style. How were things said? What makes a passage interesting or exciting? How did the author introduce a new subject or finish with an old one? Why was the dialogue convincing and what made the characters realistic? You can improve your own writing a great deal by studying how others have done it.
You will also come across passages which you think are badly written. When this happens try to rewrite them. This is always an excellent exercise for improving your powers of expression. But, beware, do not try to copy another’s style. Let your style develop naturally from your own ability, opinions and emotions.
Aside from reading other works, you can also acquire new knowledge not only from books but also from individuals and from their experiences of life. To learn from individuals it is necessary both to be a sympathetic listener and also to develop a reporter’s skill at asking questions which will elicit the maximum information. If you do not understand what you have just been told by the person you are interviewing you should always ask for explanation. Never be afraid to confess your ignorance. If you do not understand, how can you possibly make your readers understand?