Commentary (And A Shameless Plug): Part Of How To Promote Your Books, With An Example

1. Definitely state why you write books (and write in general) and why you want to continue to write books (as well as in general), especially if you want to become or continue to be a full-time author.
2. Suggest for what people should buy your books: e.g., for leisure reading, as belated holiday gifts, to support you as an author
3. Appreciate when someone does buy a book of yours, and even give him or her a shoutout.
4. Be persistent and timely in promoting your books, and "be persistent" does not mean "be harassing" or otherwise "be annoying". If others can and want to buy your books, they will. Likewise, "be timely" does not mean "be badgering" or "promote your books for every occasion and at every interval possible". In fact, being badgering and/or exploitative of every occasion will only be wasting your time and your potential audience's time.

Example:

PS Promoting the books four times on Facebook within five days was enough for now, especially with promoting them once today.