Sandlot Sluggers

The hardest part of getting this isn't the actual hitting a double, because any hit in the alley with the fire bat will probably net you time for a double. Getting the actual powerup is the thing, because it's random. Once you get it, just wait on the pitch and swing, if you hit the gap with it make sure to press LT once you get to first base to continue on to second base, do this even if you think you wouldn't get a double normally, because the fire part of the ball will burn the player trying to pick it up.

If all else fails remember you can bunt for this with two controllers in a pick-up game once you get the fire powerup. Once again pressing LT after hitting first base to keep your player running to second or further.