I am in the process of designing a diary study to investigate the interaction between a current software application and its users. I am seeking open-ended data and insights from users that I might not otherwise get from a survey. The users are free to put anything they want in the diary, but to also provide some direction the diary includes daily prompts to the user.

I'm having a little trouble designing some of the prompts used during the diary study, however. I have questions like:

* Describe something in the application that makes your work day easier
* Show a screen shot of something that frustrates you

I'm sort of winging these questions, however, and I was wondering if there is any research out there that investigates what types of questions yield the best results for a diary study, or if there are any existing case studies I can use as a model for how I should be creating prompts within the diary.