At Pocket Gamer Connects San Francisco 2015, Mickey Maher, Senior Director of Business Development at Unity Technologies, gave a talk on the best practices for ads.
He pointed out that developers now know that ads are a required part of monetisation, as "if you're lucky, you can coax 3% of your players to play".
Create the desire
Maher said that "if you want to maximise revenue through ads, create that desire to watch them", using the example of Crossy Road which rewards players with coins for watching ads after they lose.
He also said that, in response to the question of whether showing ads for other games affects player retention, "no it absolutely doesn't".
You can see all our videos from Pocket Gamer Connects San Francisco 2015 in this YouTube Playlist.