Offer a minor report and get the opt-ins BEFORE you send them to the sales page. As soon as they enter their email, have it send them to a blank page that says something like
"Thanks for requesting the free report '10 ways to feed your turtle pork chops' Check your inbox in 15 minutes for the download link. First, I can't wait to show you this information on 'turtle feeding' here."
"Click Here if this page doesn't redirect in 10 seconds"
Make it redirect in 10 seconds to the sales page via your hoplink.