Command and Conquer 3 Walkthrough GDI Mission 7, Cairo

You are now charged with destroying a NOD nuke silo and command headquarters. Concentrate your early efforts on getting to a tech center, starting with a crane, while preparing to expand to the rich tiberium fields to the east. Build plenty of infantry to go to the eastern side to defend it. Don't skimp on the missile squads! Put two harvesters on each of your two fields once you're settled then build an additional barracks.

Build an expansion to the east, consisting of two refineries and a surveyor (unpacked). Afterward, continue up the tech tree while building one air field with four orcas. They will be your suicide squad to send to take care of the power plants while other operations are going forward. In order to get them safely to the power plants when the clock is looking a little scary, send them up the western side of the map until they are just west of the power plants, then target them all on one and let them die. The nuke silo needs all three to function, so just one will do.

Now, build a surveyor and use the call transport ability. Send it to the northwestern corner of the map and deploy it near the blue tiberium field. Send also an engineer to capture the tiberium spike. Prepare two war factories and a guardian cannon at once to be set down immediately once the area is in your control. Some NOD patrols may come harass your new installation, but they will be hard pressed if you start first with APCs followed by a few predators. At that point, research the rail gun upgrade for your tanks and start pumping mammoths out of the two recently constructed war factories. Back at your base, for good measure, you could also make a point to train zone trooper squads to make the 'Destroy all NOD structures' objective easier.

Eat the enemy from the inside out. Hit the power plants with your orcas or your mammoths. Once you've got a decently sized army send them in with the attack move and start destroying things. Save the northeastern corner for last so that you can obtain completion of all objectives. When you feel ready, you can even send in your zone troopers for some extra fun!