you must grab your audience's attention with a salivation-worthy hook. Who is your target market, and what kind of click-bait header would they be unable to resist?
hold their interest by offering them something of value, whether or not they intend to buy. Your chances of converting the sale are slim to none if people aren't at least still reading.
create the desire to buy. In what ways will their lives improve by purchasing your service/product? Is your free "interest" section so strong that they can't help but want to see what your paid services look like?
plant that big blinking Call to Action button where your reader can't fail to miss it--and voila! A SALE!
For more great tips, check out Neville Medhora's short self-help guide "This Book Will Teach You to Write Better."