IEC 61499 is a standard for developing industrial automation systems. It is known for its reusability, reconfigurability, interoperability, and portability. However, during their life cycle, industrial systems need to evolve according to requirements, and modifying the applications to satisfy these requirements can be complex and error-prone. This paper proposes techniques to guide the evolution of IEC 61499 applications. Given an initial application and the evolution requirements, we generate guidelines for modifying the application to satisfy the requirements. The application is first translated into a behavioural model describing all possible sequences of events the application can trigger. We then apply algorithms to extract relevant submodels of the application and modify them according to the requirements. Finally, the submodels are analysed to generate guidelines for modifying the application. These guidelines can bridge the gap between the requirements and the target application. Instead of only considering the requirements when exploring possible modifications, the developers can use the guidelines to make necessary changes to the application. A mixing tank system is used as a running example to illustrate the approach. In addition, a prototype to automate the evolution techniques is developed.