OK LOL now I see what you were talking about in the other thread. Now to answer your question you have to be completely honest about how much you believe in your own product. A sales page like this is what you do when you have a garbage product you hope to talk some morons into buying.
This is how real books are sold:
Detect Deceit: How to Become a Human Lie Detector in Under 60 Minutes by David Craig | NOOK Book (eBook), Paperback | Barnes & Noble
1. A legitimate distributor - You can publish ebooks through all the big guys now. You get crazy potential for distribution, perceived legitimacy, an effortless buying process and can target all the major devices in a native format.
2. The overview is your sales copy. On a lot of these self help books it's pretty salesy, but not desperate. For the most part it's genuinely informative but done with a favorable slant towards the author and content.
3. The price is right there. $15 is pretty reasonable. You really don't have to prequalify people before you show them that.
4. There are reviews. If you have a decent product you'll welcome honest reviews since they're worth more to a customer than anything coming out of your mouth.
5. There's a sample. When you buy books in the store you read a bit first and the same thing happens online. The best way to sell a good book is to let someone start and get them hooked. If you actually believe in your product there's no excuse not to let that happen.
Now if you're trying to pull a fast one then work the sales page, but if you're actually an author and not a bullshit artist it doesn't make any sense to go that route.