You can't make people do anything. Like any product you sell or promote if you want people to purchase the product you have to show them that it creates more value to own it than not too.
Why do you buy from Amazon? If not why not? Focus on the value. And to be honest I am not a big fan of Amazon. They offer little in the way of real customer service.
However in some niches there are few alternatives because they have so many items. And for some people in certain communities their choices are to purchase online or drive for miles and hope they can find what they want.
Amazon's best feature is their user reviews.