There so many comments, so here is my suggestions (notwithstanding that someone may well have given you this answer:

Don't write! Speak!
Get Dragon naturally speaking 10. Take your first topic, bullet point sand all. Think about what you would SAY. Then SAY it. speak it into the Dragon until you have said what you want to say. It'll come out the other end as word processed text, Then you can edit it, knock it into shape, or get a professional editor to do it for you.

Once you know what you want to say about a topic, you can get the book done in a month. As far as topics go, start off with something deeply based in your own experience. Having listened to quite a few of your videos online, in my view, there is a lot you can draw on.

Best of luck.

Max