Interface metaphors facilitate the learning of new computer systems by supporting the transformation of existing knowledge in order to improve the comprehension of novel situations. However, there is very little guidance for software designers on how to select, implement and evaluate interface metaphors. This paper, which is based upon extensive work in developing metaphors for telecommunications systems, provides a framework for software designers who wish to exploit the use of interface metaphors. The paper proposes a set of six design steps, to provide designers with a practical approach to the application of metaphor in the design of interactive systems. An explanation of the activities required in each step is given and justified from experience gained in developing a number of interface metaphors. A pragmatic model of the use of metaphor in human centred system design is introduced, and a technique for eliciting metaphor characteristics is developed from ethnomethodology. The approach has been discussed with software designers at two workshops, and the final content has been influenced by their input