If it's about a franchise/series I already know of: I just buy it. Aside some pictures here and there; don't actually do any research. If I happen to be on a site/reading a magazine and there's info about it I read it; but I don't actually look for info about it. (Mario, Zelda, Pokémon, Mortal Kombat, Resident Evil, Assassin's Creed, Uncharted are examples of this... etc.)
If it's about a new franchise/series: I look around for more info across multiple places (forums/people's opinions, magazines, websites. Though, to actually be interested in this new game I have to be interested at least on the visual style/design. Not the amount of textures or polygons (i.e. Child of Eden = overall visuals, Assassin's Creed = Always loved Altair/main character's design, etc.) This was also the reason I gave Assassin's Creed (as a series) another chance (was really disappointed with the first game, but still liked Altair and liked Ezio's look too; so got #2. One of my favorite games from back then)