Before writing books, start writing articles. You should have full information as well as knowledge about the subject on which you write. It is also better to write small books. You can add some relevant subjects to make it more attractive. It is considerably even better to do bad works with awareness, but not good works without awareness. The things you do without awareness may affect others towards wrong knowledge.
Before writing something, note all your thoughts in a separate piece of paper. Read it carefully, edit it several times, and remove unwanted words and sentences. If you have a thousand words, you can bring them down to a hundred words and still convey the same thing. If you go on correcting at every step, your writings will serve your purpose and the readers will get benefit from your book.
As told by: Shivapuri Baba