Researchers must excel at writing to effectively engage the scientific community. Clear and engaging writing advances new knowledge and increases the impact of a researcher's work. As developing researchers, it is essential that graduate students learn to write clearly and effectively so that their work is accessible to their peers and colleagues. An essential part of graduate school education should include the teaching of formal writing skills. In most graduate programs, students learn formal writing skills from two sources, their advisors or a writing class. We identify a third source: the graduate student peer group. In this paper, we describe how we leveraged the existing collaborative research dynamic among students in a graduate research lab and created a writing group, similar in spirit to the concept of a reading group. We describe the inspiration, implementation, and impact of a writing group in a real-world research lab. We show how the writing group started organically after a PhD student took a graduate writing class in the Computer Science Department and thereafter initiated the writing group in his research lab. We also describe how a writing group can be implemented in other research labs to improve the writing of graduate students worldwide.