One of the common stumbling blocks of writing a game is that you end up in a sprawling mess. You start out writing a WW2 skirmish game and at the end of it you are writing rules for the divisional supply depots and how to handle hover tanks. How did you get here?

Well, the answer is that you got there gradually because each section builds upon the last. Its difficult to hold 200 pages of game in your head at one time so as you work you will tend to gradually shift things in and out. This is probably not how psychology actually works but to me it always feels like a conveyor belt. We just got done writing the morale rules and now we are on to leadership rules, so whatever section was before morale can get discarded. As a result sections can slowly get further and further from the original objectives as each deviates more and more. 

A common place for this to occur is in the special rules section of your game. This is the place where everything from paratroopers to demolitions goes and is a great place for all manner of over-detailed sub-systems to hide out. If your core rules are all "roll 2D10, apply modifiers and compared to a target number" and then the rules for sabotaging railroads is a dice pool with exploding dice and drawing from a card deck, this is what happened.

With experience you get a feeling for when this starts to happen and a critical reading (or having some serious feedback from someone you trust) helps weed it out. When you are just starting out however, it can be more challenging.

What helped me a lot was to write down my objectives up front. You can even put it in the first chapter of the book if you like, but otherwise a notepad, sticky note or your white board will all do.

These objectives can be about the scale of the game ("platoon level, infantry focused"), mechanical concepts ("dice pool with 3-6 D6s") or broad claims ("Ranged combat is primarily suppressive"). Try not to go overboard with too many: You are really just trying to nail down the 4-6 most important things that will keep the game together. This can easily double as the elevator pitch for the game as well, since this is basically what will end up defining your game.

It can also help to sketch out the list of content in advance. How many "special cases" do you want? Are you going to cover air units? Buildings? Magic? I always try to write the chapter headings first and I'll often fill in some expected sub-chapters in advance to help narrow down what I intend to do. 

When you are going through your project, stop every now and again and review your stated objectives. You can do this at the start of each writing session, at the end of each rules chapter or once a week, whatever seems to work. Compare what you have written lately to the objectives: Are you on track? If you deviated, did you do so for a good reason? Should you go back and rewrite something or make it an optional rule? 

If you find you are constantly bumping up against your objectives, you may have misjudged what kind of game you actually want to write. We will talk about that in a future post.