Acquiring complex oral presentation skills is cognitively demanding for students and demands intensive teacher guidance. The aim of this study was twofold: (a) to identify and apply design guidelines in developing an effective formative assessment method for oral presentation skills during classroom practice, and (b) to develop and compare two analytic rubric formats as part of that assessment method. Participants were first-year secondary school students in the Netherlands (n = 158) that acquired oral presentation skills with the support of either a formative assessment method with analytic rubrics offered through a dedicated online tool (experimental groups), or a method using more conventional (rating scales) rubrics (control group). One experimental group was provided text-based and the other was provided video-enhanced rubrics. No prior research is known about analytic video-enhanced rubrics, but, based on research on complex skill development and multimedia learning, we expected this format to best capture the (non-verbal aspects of) oral presentation performance. Significant positive differences on oral presentation performance were found between the experimental groups and the control group. However, no significant differences were found between both experimental groups. This study shows that a well-designed formative assessment method, using analytic rubric formats, outperforms formative assessment using more conventional rubric formats. It also shows that higher costs of developing video-enhanced analytic rubrics cannot be justified by significant more performance gains. Future studies should address the generalizability of such formative assessment methods for other contexts, and for complex skills other than oral presentation, and should lead to more profound understanding of video-enhanced rubrics.