Don’t write interview guides
If you are going to meet with users and do some qualitative research then I expect (hope, even) that you have had it drilled in to you to carefully construct an interview guide. Now, I ask you to remember that lesson, but throw away the interview guide!
The very reason we take the time to go and meet with our users is to learn from them and to discover new insights about their behaviours, needs and desires.
The very concept of an interview guide implies that you are taking the lead and guiding them. Which, in turn, implies that you know what needs to be talked about ... so what is the real chance of uncovering new discoveries here?