Researching For a Game
Most of the research done before making a game is thinking about other games you have played before. This is the easiest and most basic form of research...it's called experience. (:D)
This is actually very important in my experience trying to make a game or plan a game with a non-gamer. (Let me tell you, it was very frustrating. Mostly there was a language barrier.)
Diversity is important. Being familiar with many different types of game mechanics will help you in the creation of your own game. I'm not just talking about digital games, I do also mean card games, board games and social games. Think about the rules of some board games. Think about the rules of those games when they were translated to a computer game. Consider playing Monopoly with the physical board against a friend versus playing it on the computer against AI.
What this should do is make you think about aspects of the game you are making. When making an RPG, think of table top Dungeons & Dragons. After creating a character, things such as attacks and defense and various other actions are based on rolling dice. Similar things happen in an RPG game in some battle systems. However, it's usually not as random as rolling a die. The randomness should favor the player.
This is a term used by gamers to describe how the various mechanics work together throughout the game. If they work well together and the difficulty matches the player's skill, then the game is well-balanced. A sudden spike in level difficulty or a battle system that seems to work against the player's favor are considered unbalanced.
The term also covers various other aspects of the game design. Things like special features for instance can be balanced or unbalanced. If you have too many special features it can crowd the game and over-whelm the player.
A game that I've played that has this problem is "Okami" for the PlayStation 2. Many symbols show up on the screen that I don't know the meaning of. There are several sub-screens for various inventory. And several "modes" that I need to go into during battle. That's a lot to keep track of. I need the manual with me most of the time to reference what icons on the screen mean.
Giving your game lots of features doesn't make it more challenging, it makes it not fun...which is the primary goal of the game: to provide entertainment.
This element may seem like fluff, but it really works when dreaming up different features. Authors, Comic Artists and Filmmakers all do research on the subject they are producing. For example for a story about horses it would be a good idea to learn various terms associated with the animal. If you call your male horse a mare, then chances are you need research before you are laughed at. (I've read an instance where an editor read such a thing by an author.)
If you have a world based off medieval fantasy, do some research about the time period.
If you have certain weapons in your game, check out specifics about that weapon, like how much it weighs.
If there is some mythological creatures in your game, read their original myths.
It will help your story in the long run if you learn a bit about the world you are trying to create. You may find out something interesting that you never knew before than can be added to the game.