Method-in-use (Nunn, Describing classroom interaction in intercultural curricular research and development, University of Reading, 1996, International Review of Applied Linguistics in Language Teaching 37: 23-42, 1999) is a description of the method actually being enacted through classroom interaction in a particular context. The description is primarily a tool for improving classroom teaching and learning, first by establishing what is in place and then by considering what could be adjusted to improve learning. The description emphasizes the use of discourse to enhance learning, considering (1) teachers' and students' roles in classroom interaction, (2) types of discourse input and creation (3) types of holistic pedagogical activities and (4) types of discourse outcomes. As a situated concept, method-in-use combines well with classroom observation when the latter has the aim not of evaluation but of improving second language acquisition in context. What is being enacted in the classroom with and through language is then at the centre of a renewal process. The exploitation of the original four-part classroom model for deriving a teacher's method-in-use is briefly exemplified using observation data from two contexts before considering observation data from a third context, the Iran Language Institute in Tehran, in more detail. Once an adequate description has been achieved providing situated local knowledge, improvement of the local situation can be attempted in relation to de-contextualized conceptual knowledge of the method concept (Richards and Rogers, Approaches and methods in language teaching, Cambridge University Press, 1986) or SLA principles (Ellis, "Asian EFL Journal" 7: 9-24, 2005).