You need several Wraiths to inflict significant damage against a target. To produce an optimal quantity of six or more, you need two or more Starports producing them simultaneously. Wraiths build slowly, and even after they're constructed, they must sit idle for some time as their cloaking energy reserves charge up.

Use Wraiths to attack your enemy where he hasn't been so wise as to deploy cloak-detecting units. Enemy flying units will quickly fall to your Wraith fleets and their deadly Gemini Missiles if they have no means of firing back. Likewise, Wraith Burst Lasers can lay waste to any ground target given enough time. Fleets of Wraiths patrolling for enemy fledgling expansion bases should destroy them without any kind of retaliation.

Wraiths quickly fall prey to anti-air defense emplacements, including Zerg Spore Colonies, Protoss Photon Cannons, and enemy Terran Missile Turrets. These air defense structures see right through the Wraiths' cloak even as they tear into their flimsy armor. Other units to be feared include the Zerg Overlord, Protoss Observer, and enemy Terran Science Vessel, each of which can detect cloaked Wraiths so any nearby enemy forces can target and eliminate them. The Protoss Observer is itself cloaked, so be especially careful of a Protoss opponent who doesn't place many Photon Cannons. Chances are he's swarming the battlefield with Observers instead. A Terran Comsat Station Scanner Sweep will also reveal cloaked Wraiths, so beware the telltale sparkling effect if you are battling against a rival Terran power.

One strategy is to deploy just a few expendable cloaked Wraiths early on. The paranoia induced by being attacked by an invisible opponent may be such that your enemy will spend vast amounts of resources making certain your next wave will be detected and destroyed. Even as your opponent doubles up his anti-air defense, use this opportunity to mount a full-scale assault using other kinds of units.

Wraiths cannot face the rival species' superior aircraft head on. The Zerg Mutalisks take half damage from Wraith missiles, while Protoss Scouts are hands-down stronger. Never throw your Wraiths into a head-on battle; rather deploy them stealthily from time to time to harass the enemy. In many cases, Wraiths are too costly and not potent enough to justify purchasing, so use your discretion early on in deciding whether or not their specialties will be appropriate your situation.

Next: Science Vessel