It might be an oversimplification, but if you can boil any successful business down to two things, they are: a great product, and great conversion.
Great conversion?That's right: no matter how great you make your product and service, it's not worth a dime if those dimes are not rolling in. To sell a product, you need to call your clients' attention to it, and that's called advertising.
And there is only one goal of great advertising: it's turning those eyes on the ads into dollars. That's called conversion.
So when those eyes hit your copy, the ideal scenario is that merely 'browsing' turns into 'buying'. How can you do that? Make that copy compelling!