Method engineering has emerged in response to the need to adapt methods to better fit the needs of the development task at hand. Its aim is to provide techniques for retrieving reusable method components, adapting and assembling these together to form the new method. Based on a survey of these exiting techniques, the paper proposes first, a generic process model supporting their integration in terms of four possible strategies for action. This model is aimed at helping the method engineer either selecting one strategy or combining several ones that best fit the situation of the method engineering project at hand. Second, the paper presents one of the four method engineering strategies embedded in the generic model, namely the evolution-driven strategy and illustrates it with the experiment done by the authors on a large scale project.