The European Union (EU) has put the concept of circularity at the heart of its strategy for transitioning towards a low-carbon economy and reducing the use of virgin resources. Concrete measures, such as clarifying rules on co-products or supporting innovative projects, have been taken in order to promote Industrial Symbiosis (IS)-turning one industry's co-product into another industry's raw material. However, one of the main barriers to the democratisation of IS remains the exchange of (confidential) data between industrial partners. Here, the concept of industrial sector blueprints is presented as a solution in order to overcome the challenge of sharing information across industrial sectors. A blueprint is constituted of a series of profiles providing insights on the key inputs and outputs of a given industry in terms of thermal and electrical energy, materials and services. A heuristic and comprehensive methodology is presented detailing a step-by-step approach for building the profiles and the type of data required. It is applied to a typical refinery demonstrating the efficiency of the method and showing how it can be used in an IS context.