There are a variety of ways in which you can demonstrate reflective and critical thinking:
Critical thinking of technical approaches:Noting the next steps with regard to the current status of the project; demonstration of foresight. Does not just describe the procedures taken but also states why the procedural steps were taken. Articulated and thorough explanations of technical problems. Inclusion of testing in the overall process. Artifacts such as decision-making matrix; DFMEAs.
Critical review of design and team processes: Identifies aspects of design and team processes that are going well, as well as problems and potential problems; can include possible solutions and plans for addressing problems. Not just a description of events but a reflection on those events.
Articulated learning: Provides examples of the articulated learning. Makes transparent the realization/learning process. Recognition of how the learning can transfer to other settings. Not just a summary. Follows a clear reflective framework: What did I learn? How did I learn it? Why does this learning matter? What will/could I or others do in light of this learning?
Please note that although it reflects critical thinking of your learning and your team, it is a professional document that will be kept with the team for future semesters.