This study explores the processes, considerations, and pitfalls of manual drafting and playtesting for board game designers. The board game manual is perhaps one of the most important items in a board game box, yet it is often neglected in game design books and other media. Through interviews with twelve board game designers and editors, this study compiles the best practices and classic pitfalls that designers encounter while writing these high-stakes documents. Observations in this study are geared toward the technical writing community, who can stand to benefit from learning more about the playful nature of game documentation and the affective data gathering processes that these designers undertake as they test their games and rulebooks. In an effort to make this data more accessible to board game designers, a Manual on Writing Manuals is included as an appendix to this study.