Well, I wrote mine back in 2003, 'Transform Your Life in 21 Days!'

Here are 3 ways to approach it.

1. Go all scientific. Dig deep into research papers, minute detailed scientific stuff. A bit dry though.

2. Claim to invent something new in the field. You could say you have come up with something new, but it's likely to simply be a twist on something already out there.

3. This is the way I went - use *personal* stories. Explain the theories in your own way, but then give proof about how they worked in your life. This make the book unique to you and a good selling point. It also means it can stand the test of time, mine was written in 2003 covering stuff I have used for 25 years +

Hope that helps,
Gordon