Codemasters' principal designer Phil O'Connor writes at length on how to hire a good game designer. Despite its dry and business-like air, it's a frequently-amusing guide on how to spot a charlatan in a profession that offers little in the way of accreditation, but which has an abundance of people who think they can do it.
The key qualification, he says, is game-making experience. For those with no development or modding skills, there must be a tangible obsession not with ideas but the mechanics of their implementation. Among the many other necessary attributes that O'Connor outlines, one other that stands out is the need for a broad interest in literature, history, music and art. Designers must also be able to adapt, because "no design survives first contact with code."
Finally, he warns teams about taking on two sorts of poseur: the Ideas Man and the Fanboy.