NN Group article: "Instructional Overlays and Coach Marks for Mobile Apps" Summary: Instructions in mobile applications must be designed for optimal scannability, as users tend to dismiss them quickly and do not read thoroughly.
Flickr. Simple and minimal.
Up iPhone coach marks, walkthroughs screenshot
Secret iPhone coach marks screenshot
Gogobot iPhone coach marks screenshot
Clever guides @Lili Weißensteiner Weißensteiner Tu