Knowledge derived from practice forms a significant portion of the knowledge base in the education field, yet is not accessible using existing empirical research methods. This paper describes a systematic, rigorous, grounded approach to collecting and analysing practice-based knowledge using the authors' research in teacher leadership as an example. Practitioners with relevant experience and expertise participated in multi-round, online panels in which they responded to several types of items, culminating in "advice to the field". Strategies used for sampling, panel implementation, and analysis are described for identifying practice-based insights that are useful to practitioners, policy makers and researchers.