Responsive Search Ads best practices?

Earlier this year, Google made Responsive Search Ads (RSAs) the default ad type in Google Ads. We're always curious to understand what our customers think about Google's moves towards automation in their tools and features.

What are your best practices for using RSAs in your campaigns? 

How do you come up with a variety of Headlines and Descriptions? 

What do you think about the Recommendations provided by Google for different Headlines and Descriptions?