The learning curve for doing a good qualitative study is steep because qualitative methodologies are often vague and lack explicit steps. We detail the formulation of the grounded theory approach in a study of patients with type 2 diabetes mellitus who made decisions while strategizing their treatment types. This undertaking is to demonstrate how this systematic and yet flexible methods contributed to the understanding of the issue we were investigating. The process from deciding on research objectives and research questions, follow with systematic process for data collection and analysis allows us to generate a substantive theoretical model. By paying critical attention to theoretical saturation, grounded theory approach enabled us to construct all possible explanatory concepts related to decision making in strategizing diabetes treatment. We also describe the challenges throughout the whole research journey, including getting permission to interview patients, gaining the trust of research participants and staying open to the participants’ views.