I was asked, "What tips can you give to someone who wants to write his first book?"
Don’t worry about it, because the first book is just practice.
Maybe the first few books.
So stop worrying and write your practice book.
If your first book happens to be a success, that’s gravy. You can control whether you win or lose, but you can control whether or not you learn.
Get the book out there and gather feedback. Then use that feedback to improve your writing for the next book Repeat this process a few times and you’ll become a successful writer.
Do you recognize this iterative development process? You should, because writing a successful book is very much like writing a successful program.
In the meantime, if you'd like some help getting that first book finished, read