What sells me? That is hard. Maybe it's easy to talk about what doesn't sell me.
But first, some comments on AlexK observations. The train of yes is a very old and widely used sales technique. It's almost cliche and I'm sure some people use it without realizing what they are doing. However, it and other techniques detonate and warning in my mind when I'm looking to buy something.
Ads are just like real sales people, but more limited. The trick is the make sure the customer leaves with a product, maybe not the one they came for, but make a sale. Ads do this my hooking into common desires, then leading you to their products. Sales people can take the time to know you and develop a rapour and then decide which product to lead you to.
The body language mirroring is another alarm trigger for me.
I'm not sold by: emotions, promises, guarantees, testimonals. I guess my need and a sense of sincerity and not overselling.
For self help material I would say they have a tough job. Because, they have to be careful not to give away the essence of the course. Note that the details of the course can often be given without giving the true value away. Also the true value is presented, but not seen or appreciated until after going through the course.
end of ramble.
Iam2 
