In this paper we present an approach and the technical guideline in preparing double degree programs and several critical factors based on our experience in conducting it. Along with the guideline, we also describe existing tools that have been available and used intensively in every program preparations and revisions at University Duisburg-Essen and its partner universities. These are the curriculum databases of the participating universities and the Double-Degree Database that contains the information of curriculum equivalencies. The main discussion of this paper is on the design process for double degree courses and the introduction of a tools box to support this process, both developed at University Duisburg-Essen.