In game: The same as any other player with common sense, a wide variety of powerful offensive moves, virtually no support or defensive moves unless they recover HP (atleast 50% per use, sunlight and moonlight being exceptions).
With non-competitive friends: The same thing, really. I'll incorporate more support moves that help the entire team, though, such as the screens or Stealth Rock.
Competitively: The strategy varies with every team. I've done Sandstorm teams before, balanced teams (this was way before I joined any forum), offensive teams, etc. I'll even use Trick Room teams when the time calls. In short, I'm a jack-of-all-trades; besides defensive teams. Stall teams ftl.