Writing a game design document (GDD) https://www.scikey.ai/slink/O4fEA is a crucial step in the game development process, serving as a blueprint that guides the entire project from concept to completion. Start by outlining the game's concept, including its genre, setting, and core mechanics, providing a clear vision for the project. Define the game's characters, story, and gameplay mechanics in detail, specifying levels, progression systems, and player interactions. Additionally, include technical specifications, art style references, and audio requirements to ensure all aspects of the game are cohesive and aligned with the overall vision. Regularly update and iterate on the GDD throughout the development process to adapt to changes and refine the game's design as needed.