Infiltrated! (Mission 3)
Turn the game speed to the slowest possible and sell the Refinery before Nod Engineers take it over. Build an Advanced Guard Tower next to one of the Guard Towers in the north. Nod will build a Cannon in the middle of your Base. Build a Medium Tank or Rocket Infantry to deal with it.
With the initial mayhem out of the way you can start building your base. Rebuild your Refinery and get the Harvester in the Tiberium fields to the east back to work.
You’ll need strong defences to the north east of your base. Preferably at least two Advanced Guard Towers and some Guard Towers. Nod will send Engineers one-by-one and streams of vehicles to attack your base.
You can incapacitate the Nod base by following this strategy. First build 4 or 5 Hum-vees and send them directly to the north. From here send them all the way to the east. At least one of them should be able to reveal the Nod Construction Yard.
While your Hum-vees are exploring build an Advanced Telecommunications Center for the Ion Cannon and 4 Helipads. Send your 4 Orcas out to attack the Nod Construction Yard. Just before they arrive use your Ion Cannon on the Construction Yard. Most or all of your Orcas should survive the attack and the Construction Yard will be destroyed.
Build 2 more Helipads and replace any lost Orcas. Do the same tactic but this time with the Nod Airfield. Ion Strike followed by an Orca attack. With the Airfield or Construction Yard Nod will be crippled. You can now launch an attack on the base and wipe them out to complete the mission.
Next Mission: Elemental Imperative