Peer assessment has great potential to improve student learning. However, assessment is not an everyday activity for students, and thus providing appropriate guidance to students is a key component of creating a successful peer assessment experience. This paper explores how to structure peer feedback in the guided process Peer-Assisted Reflection (PAR), by comparing the artifacts and practices associated with three different iterations of PAR in undergraduate calculus. The iterations are referred to as the Questions, Critique, and Balanced approaches. Through a detailed analysis of this design-based research project, new insights are generated about how particular artifacts shape the feedback provided by students. In particular, students in the Balanced approach provided more succinct feedback across a greater variety of categories. In contrast, the Questions and Critique approaches had longer, narrative feedback, and it was focused on few categories.