The Swedish Armed Forces have adopted a new method of system development based on models. Model-based system development means that information during the development is captured and represented using models rather than textual documents. The model-based approach has several advantages such as improved traceability and a clear separation between the systems functionality and technical realization. The models could also facilitate communication between technical and non-technical stakeholders. Models are often created and presented visually as diagrams. This visual aspect is the main facilitator to the models communicative advantages. To be able to reap this communicative power the visualization of the model needs to be cognitive effective. This means the recognition and respect of the human mind´s potential to interpret and read visual representation like images and symbols. In this report scientific literature regarding creation of cognitive effective diagrams have been summarized and matched with the area of user-centered design. The result has been the formulation of guidelines supporting modeling. These guidelines encapsulate examples and suggestions on how to consider the reader of the diagrams. This is done with the aim of creating effective diagrams, which minimizes the risk of misunderstanding.