Learning how to write is of key importance for students' success in higher education and beyond. This research project aims to design instructional principles that help teachers to teach students in secondary education to write argumentative texts. Current research shows that in order to be able to write high quality texts, students require conceptual knowledge on what defines a high-quality text. However, within writing research, insight in how to build conceptual knowledge is rather scarce. Other domains such as Physics and problem-solving point towards how comparing exemplars develops conceptual knowledge. The question arises to what extent learning from exemplars through comparing also extends students' conceptual knowledge of text quality. How does the learning process occur? Does it improve students' own writing and in which conditions? From previous research we can only assume that students will learn from comparing exemplary texts. Investigating the questions mentioned above through research is essential. Using a quasi-experimental design, together with data collection in an authentic school setting will provide answers. Moreover, this research will result in evidence-based instructional design principles to teach students how to write argumentative texts in secondary education.