Basically it is your typical though IS reality, see it happening and it will happen, nothing happens without you bringing into being, rap. Lots of good stuff in there about how to manage thoughts to not self-sabotage your efforts, how to make gratefulness into a creative process (something that I meant to weave into Sorcerers Secrets, but kinda forgot) and other decent tidbits.
The downside is that there is no concession to reality whatsoever. The book actually states that Fatty Foods will only make you fat if you THINK they will... They point to people who seem to be able to eat anything they want without loosing weight as the proof of this.
Are there people who can eat junk and not gain weight? Yes. I know several. They all either exercise intensely or have digestive problems. Otherwise they have managed to make "all they want" into half a plate of everything. They are not downing 12 white castles every day, laying about all night and staying perfectly healthy.
Thought is a thing, It does indeed have a power all its own, but unless that power is harnessed through skill, it just doesnt do the kind of things that the Secret claims it does.
That said, I think that the good outweighs the bad with the book and can see why it has sold so many copies.