Now go to the very beginning of the doc and write a Statement of Purpose. What's that? This is what you are going to give people when introducing them to your project. It is a brief (2-3 paragraphs) description of what you want your game to be and why you think making this kind of game is a good idea. You will be refining this paragraph continually as your design becomes more firm, and it may very likely end up in all your help wanted ads and on the back of the box when you finally sell the game, so try to be as clear and eloquent as possible. This is like a FAQ in paragraph form, trying to anticipate the questions of anyone who has just found out that your project exists and wants to know more.
Try to answer the following questions:
- What is your game's working title?
- What genres is your game?
- What few existing games is yours most like?
- What is your game's setting?
- What is it like to play your game?
- Who is the PC?
- Why will people like your game?
- Outline the plot in about 3 sentences.
- What is your gimmick/hook?
- Who should someone contact for more info?
- Where is your webpage?
Congratulations, you now have a rudimentary design doc! ^_^ Time to look for a concept artist!