What happens after people click on your Google ad or some other link to your website? Marketing guru Seth Godin, on his blog, says to make sure you use numbers and bullets - "people don't read online, they scan" - and photos that communicate your message. Also, give people a place to go from that page since the Web is incredibly efficient when it's a road and inefficient when it's a dead end. "The best meaning-building delivers the reader to a new place, in context," he says.
Don't be afraid to compare: Saying something is better than something else helps people to understand what you are offering. And if you have to write long to tell your story, that's okay - as long as it is broken into chunks.