If 1,000 people visit your site, 90% of them are not going to buy from you. Most of them are just browsing.
Marketers spend thousands of dollars trying to segment these visitors into the ones who are ready to buy. And the ones who have already bought from you are the most valuable of them all (we all know it's 10x easier to market to an existing customer than to gain a new one).
Want to know the secret, sure-fire way to get your most profitable marketing message in front of your most "hot-to-trot" visitors?
The "Thank You" page.
A "Thank You" page (usually with the URL "/thank-you") is the page that John automatically redirects to once he fills out your form. The only reason anyone would ever visit this page is that they filled out a form or made a purchase.
Re-read that. The only people who see your thank you page are the ones who have proven that they're ready to buy.
Why do businesses always have the lamest Thank You pages then? It's usually just "Thanks for filling out our form. We'll get back to you soon!". It's like you don't even care to nurture or market your most valuable visitors!
At the very least, you could take my boilerplate Thank You Page Copy Template and customize it on your business. It's not industry-specific, but it'll still be 10x better than what you have already.
Some additional tips: