Turn 404 pages into landing pages
When someone clicks on your website from a referral link or a Google search, they expect to land on a specific page. But if this page isn’t available, they'll land on a useless 404 error page.
These pages can easily become one of the most frequently visited places on your site but most of the visitors will bounce. So instead of displaying a classic 'oops' page, use it to prompt your visitors with something of value and a call to action.