Basic outline of the pressure-expand strategy based on map control and solid pressure without turrets*. Good for directing pressure in pubs where team skills and understandings vary from game to game, marines generally have a mind of their own, or if your too lazy for a microphone :).
Not a perfect Comm game, but the key is to lever early game marine power and capture a forward point on the opposite side of the map (with lots of marines if necessary), then play the control advantage in a no nonsense reactionary fashion.
*Refrain from using turrets unless you absolutely need to, not fun for anyone! :p