Another thing that should be mentioned is timing. I noticed that Cut the Rope put in a request right at the end of the first group of levels, and to boot, they made the final level of the group really easy to get you feeling smart and euphoric. Sure, 5 stars!

While I'm not sure what the "euphoric moment" will be in my app, it's very wise to time your reminders to be placed in strategic areas associated with positive emotion: the end of a task, a major completion.