Games create stories. Rules imply the stories that a game can tell.
— Darrell Hardy (@HardyTales)
Don’t confuse depth with complexity.
— Grant Rodiek (@HerrohGrant)
One point that cannot be stressed enough: Complexity creates problems, simplicity solves problems.
— Reiner Knizia (@ReinerKnizia)
Game-sense: Got a practical problem with your board game? Don’t add more stuff. First, try using what you already *have* in a new way.
— Brett J. Gilbert (@55cards)
If you have an idea, do not give up on it. Fight for it. You will eventually win and I promise you, it will be an amazing victory.
— Chevee Dodd (@cheveedodd)
When a game has a rulebook section called “Commonly Overlooked Rules”, you have to ask yourself why are they overlooked and are they needed.
— Grim Tree Games (@grimtreegames)
Your game is always more difficult and complicated than you think. Always.
— Eric Lang (@eric_lang)
It’s never easy to shelve an idea that excites you. In fact, I’d say that it’s one of the most difficult things to do as a new designer.
— Patrick Nickell

Things to avoid in game design. Thou shalt not…

http://boardgamegeek.com/thread/816102/things-to-avoid-in-game-design-thou-shalt-not

Thou shalt not publish without a great deal of playtesting.

Thou shalt not become enamored of thine own ideas.

Thou shalt not make the prototype too elaborate.

Thou shalt not post on BGG forums during designated design time.

Thou shalt not be afraid. Once your game is good and polished, get out there and market that sucker.

Thou shalt not add to fix a problem, thou shalt remove.

Thou shalt not design games that must be played in the “spirit of the game.”

Thou shalt not give up…

First know what to say, then work out how to say it: Words without message are mere noise. Design without content is mere decoration.
— Reiner Knizia (@ReinerKnizia)
Spend some time creating games just for the fun of it before you decide it’s the right choice to make it into a business venture.
— Colby Dauch (@PlaidHatGames)
When designing #boardgames, sometimes you just have to throw out the theme and do something else.
— Paul Owen (@PaulOwenGames)