Almost all manuals on Game Designing or Game Business recommend you to define the target audience for your game. That’s clever, since it can be really useful in order to define what your game is going to be.
Alas, almost all of them suggest that you define your target audience in terms of demography, with emphasis on age and gender. And that’s not smart. Let’s say, for example, Wii Sport Resort. It’s a game to play with friends, and it’s being played by anybody that can throw a party at home (or even at office): from children to grandpas (grandpas really liked the Wii, do not forget). Male and female alike. Does it means that the target audience of this game was “universal”?. No, it was not. And what about Tetris?
There is a better way. Instead, try to name game genres, real games titles, and platforms. If I tell you that the target audience of this game is Flappy Bird players, PC gamers who play Call of Duty online won’t even come to your mind, even though male teenager are a huge portion of both groups.
Mobile, console, PC; Casual, hardcore; multiplayer, single player; Indie, Tripe A; Arcade, adventure, puzzle… Are better words to define the target audience for your game. And even better are game titles.
Whilst it doesn’t sound very academic, it’s certainly a better way to communicate your ideas and envision your path.