Feedback isn't something I've really had to work for. I have contact forms on my websites which people get to from the support link in the app store, and I've put my email in some of the apps. In addition to the reviews I also get emails whenever somebody has a suggestion or a problem.

If you have something really broken it will show up in the reviews pretty quickly, otherwise plenty of people email me letting me know what they'd like to see in future updates.