As I've been working on The Glow, as well as getting our iOS game ready to ship, some thoughts have occurred to me. In a nutshell, it would be, Plan Big!!
Do not design your game, then add on a "wishlist" of possible features. Put those additional features in the design from the start and plan out your schedule accordingly.
Why? Because no one ever finishes a game and says, "wow, we have all this extra time and money, what features can we add in?"
In reality, once you've got the design for your game nailed down, you have to accept the fact that not all of those features will be making it into the final release. As your deadline approaches, or as your budget begins to run dry, you will find yourself going through all of the features you have left and making the tough choices of "what to cut".
Our iOS game is a perfect example of this. The game itself is quite simple. It was also prototyped very early on. In our redesign, I had added in a handful of features (nothing huge, just expansions on existing game elements). Lo and behold, most of those added features have now been cut from the game.
In our prototype, there were a few features that were also cut. The time it took to rebuild for the iOS platform, as well as add in those features, in the end, left very little time to experiment with anything new. Now, as we're getting close to our deadline, the smart choice for us is to simply forget the added features.
The simple fact is, there is always going to be something more that you want to do with your game. ALWAYS. But a finished game on the market is worth infinitely more than a 12 page wishlist of the world's greatest features. Also, if the slimmed down version of your game doesn't do well on the market, its a safe bet that those added features wouldn't have saved it anyway.
So, as I continue my work on our other games, my advice to you (and myself) is to follow these steps.
1: Design BIG
2: Prototype Core Gameplay
3: Build the Game, Starting with the Core Gameplay
4: As the deadline approaches, relieve pressure by cutting features that haven't been finished yet.
5: Test, Polish, Release
6: If the game does well, consider DLC, expansions or a sequel to include the features that had been cut.