Have a spy infiltrate one of the following structures for the corresponding effect:
Construction Yard: Reveal fog of war from the building radius of the enemy Construction Yard.
Power Plant: Shuts off enemy's power for thirty seconds.
Refinery: Steal $2,000 from your enemy.
Superweapons: Reset the cool down counter back to its original time.
Technology Structure: Temporarily stop production of tier 3 units or structures. It also will reset the enemy's radar, leaving only portions of the map where their units and structures are visible.
Unit Production Structure: Shut down the production structure for thirty seconds, making unit production and repairs impossible. You will also see all units produced from that structure for a short period of time.
Use a Cryocopter to shrink your MCV while it is in Pack mode. While the MCV is shrunk, unpack it. You will have a mini-Construction Yard, allowing you to build your structures twice as fast. Note: The shrink ray only lasts for a short amount of time. Also, while your Construction Yard is mini it will have very low defense.