-Air units 30+ (mostly bombers) are useful against ACU or Commanders.
-Try using ranged weapons against enemy defenses outside their range. This should ensure your attacking units are covered.
-Build two Tech 3 strategic missile launchers (Nuke Silos) and put them on auto build. Launch two nukes at a time by selecting both silos, as the enemy will build one anti-nuke defense. This will guarantee a hit.