If you test with only gamers, don’t expect it to ever go to mass market – expect it to be beloved by gamers, and that’s where you’re going to sell it. So you have to figure out ahead of time who the market is that you’re aiming for, and that’s where you test it.
— Dominic Crapuchettes (@DCrapuchettes) of North Star Games (@NorthStarGames)

City Hall designer Michael R. Keller (@vhgames) discusses gut-wrenching decisions, low downtime, juggling multiple projects, market mechanics, humility and more:

“It is valuable to have several games in development simultaneously to avoid getting into a design rut. If one game presents a persistent problem, you can set it aside for a while until inspiration strikes.”

“The first time you think your game is done, you’re wrong. The next hundred times you think that, you’re still wrong.”

“Don’t ever dismiss a playtester’s feedback. You may know your game better than the player, but the player knows what it feels like to play your game better than you do.”

http://bellwethergames.com/featureddesigners/198-michael-keller-interview.html