You need to get a Judas Warlord and start having all enemy machines you capture start attacking enemy factories. The enemy has a vast amount of resources. Capture constructors as well and have them deconstruct as you drive around using the treachery weapon. You need to keep moving and keep using the treachery device. Avoid wraith reapers as much as you can; I usually destroy them using the rocket launcher and device, assuming there are no other machines around.
Using the follow command for any machines you capture is a great idea, that way if you're in trouble you can fall back and have your followers destroy anything that tries to kill you.
I usually start the mission by going north and then attacking the factories to the northeast and work my way counterclockwise to the map.
Having more useless machines "stand ground" over where factories used to be prevents the enemy from rebuilding.
Primary objective: destroy factories
Secondary objective: always having at least one Judas