MMO: Tank, craft and gather. Encourage active chatting in parties so I can meet new friends.

RPG: Usually I don't have much choice in these, although I'll note that I tend to overlevel where possible so the fighting is easier (it generally leads to more gil, too) and I can focus more on the storyline without being hindered too much by the constant battling. Oh, and if it's a good vs. evil decision, I almost always go for the good guy decision.

Single Player FPS: Snipe who I can from extreme distance. Then take a defensive position and kill almost everyone from there. I use a variety of weapons depending on the game.

Multiplayer FPS: Shoot first, ask questions later. Such as "Oh, are we not supposed to run in with all guns blazing?" I mean, I respawn, so I don't mind so much if I die. And it also (in most games) allows others to focus on being clever since I work as a fantastic decoy. This is accurate for explaining how I work in both co-op and versus, although I don't play versus often at all. I adore co-op games.

4X: Research, research, research. Keep good diplomacy until you're streets ahead of everyone and them BAM, tanks vs. chariots.

Fighters: BUTTON MASH HOOOOOOO