I started creating new landing pages for each AdGroup but initially, I still did not get the results I wanted. I started rewording my landing pages with obvious keywords from the AdGroup and repeating my title and/or descriptions somehow on the pages. I also created text that was about the specific problems and solutions for the audience for each separate page (every page offered the same solution but the difference was the reference to the industry/people that I targeted). Bingo. My conversions kicked in.
Not sure what you are referring to about the downloads unless that is specific to your industry.
For my site, my conversions come from emails or phone calls asking for more information on the services I provide.