I published one of my thesis as a book. Always tried to get into writing a mainstream book, but working against a self set deadline with all the "other" distractions in life is tough.

What I can recommend you is taking a look at "Steve Manning How To Write A Book On Anything In 14 Days or less". Even so the title sounds very scammy and marketing'ish it provides really a solid advice for non-fiction books and gives a very structured approach. You can find of cause copies of it in various online "repositories".