Content quality: You will earn Google AdSense revenue only if people subscribe to your feed. The more subscriptions you get, the better are your chances of success with AdSense for feeds. Since most people would be looking for quality content, you need to make sure that your feed contains up-to-date quality information that is presented to the users in an easy-to-understand language. Besides that, the feeds should be free from grammatical and spelling mistakes.
Content quantity: Include as much content in your feeds as you possibly can. Again, the aim is prove that the feed is useful and comprehensive (so that more users subscribe to it). If you feel that the complete article cannot go into the feed, include a good summary of the article.
Limit the ad units: If the users find that your feeds contain too much Ads, they might not subscribe to your feeds at all (and the whole purpose of feeds would get defeated). In order to ensure that you get good subscription to your feeds, you should limit the ad units to one per feed. Another good way of ensuring that your feeds dont look like an advertising medium is to place the Ads either at the end of article or after having sufficiently discussed the topic.
So, get ready for enhancing your AdSense for feeds revenue with these tips. Your wait may soon be over. Keep the tempo going and keep checking Googles AdSense blog for updates about the launch of AdSense for feeds.