You can make a good amount of income by writing some eBook on the topic that you are much familiar with. There are so many sites that allows self publishing of the book and you can promote the book that you have written through your website or blog. The websites like Amazons can help in selling your book. This website has already witnessed the pace with which the eBooks are getting sold. There are many genres like mystery and thriller that are getting more customers and so you should try to write an eBook on any of these categories.