Context: Software engineering researchers and practitioners rely on empirical evidence from the field. Thus, education of software engineers must include strong and applied education in empirical research methods. For most students, the master's thesis is the last, but also most applied form of this education in their studies. Problem: Especially thesis work in collaboration with industry requires that concerns of stakeholders from academia and practice are carefully balanced. It is possible, yet difficult to do high-impact empirical work within the timeframe of a typical thesis. In particular, if this research aims to provide practical value to industry, academic quality can suffer. Even though constructive research methods such as Design Science Research (DSR) exist, thesis projects repeatably struggle to apply them. Principle solution idea: DSR enables balancing such concerns by providing room both for knowledge questions and design work. Yet, only limited experience exists in our field on how to make this research method work within the context of a master's thesis. To enable running design science master's theses in collaboration with industry, we complement existing method descriptions and guidelines with our own experience and pragmatic advice to students, examiners, and supervisors in academia and industry. Method: This paper itself is based on DSR. Based on 12 design science theses over the last seven years, we collect common pitfalls and good practice from analysing the theses, the student-supervisor interaction, the supervisor-industry interaction, the examiner feedback, and, where available, reviewer comments on publications that are based on such theses. Results: We provide concrete advise for framing research questions, structuring a report, as well as for planning and conducting empirical work with practitioners.