How do I write a product page that sells?
Updated
Say what it is in the first line
Say what the product is in the first line, in plain words: "A spreadsheet that tracks freelance invoices and tells you who is late." The reader should know what they are looking at within five seconds. Then answer who it is for, what they get, what format it is, and what happens after they pay.
Clever headlines lose more sales than they win.
Answer the four questions buyers have
Who is it for? What do I get? What format is it in? What happens after I pay?
Every unanswered one is a reason to close the tab.
Show the inside
Screenshots, a contents list, a sample page. People buy what they can see and hesitate over what they cannot.
This does more for conversion than any amount of persuasive writing.
Cut the fluff
Delete anything that would be true of any product. "High quality", "carefully crafted", "one of a kind".
Replace it with specifics: page counts, file formats, how long it takes to use.