— In the context of service-oriented computing, services provide the capabilities necessary to support the business, especially its processes. Within the service modeling process, the services that constitute a common and stable basis for all supported processes have to be identified. The consideration of each business process on its own, without guidelines, may yield a service inventory that is not adjusted with all requirements, and for instance contains several services providing the same capability, having an inappropriate granularity, or using different taxonomies. Thus, this paper suggests applying rules on a model capturing relevant business requirements to systematically derive a blueprint as a proposal of necessary services. The approach is exemplified by a scenario at the Karlsruhe Institute of Technology (KIT), where it is applied in the context of module catalog management. Keywords-service modeling, service inventory blueprint, service candidates, rules