General Strategies and Tactics

Knowing Unit Counterbalance
It is important to understand which of your units best counteract the enemy and to build up your force accordingly. The first step is to scout out the enemy base and take a look at where he is allocating his resources. No one type of unit is invulnerable; every race has a means of effectively killing each and every unit belonging to the other two races. For example, a Protoss general who discovers a Zerg opponent building fleets of Mutalisks would be wise to ready his High Templars whose Psionic Storms can quickly shred the Zerg airforce. However, Psionic Storm will not prove as useful against a Zerg commander focusing on Zerglings and Ultralisks whose close-range attacks make the spell too dangerous to use, for fear of harming your own forces. Meanwhile, should the Zerg discover a Protoss opponent bent on building up his own airforce, they must promptly research the Queen's Ensnare ability and prepare to use it in combination with the Scourge suicide bombers. Unless faced with a substantial enemy airforce, hatching Scourge is a waste of time and resources.

Meanwhile, Terrans facing Zerg or Protoss must be ready to train Firebats and station them in defensive Bunkers, as Firebats are adept at holding off large packs of Zerglings and Zealots. And should the Protoss or Zerg discover the Terran's intention, they are in turn advised to focus on long-range units that can kill off Firebats before they come close. While to characterize all such relationships through the typical rock-paper-scissors model is to generalize much too broadly, the key here is to understand that certain types of units are better suited to dealing with specific situations and enemies than others. You must strive to discover and learn to anticipate what sort of units the enemy will send your way or use to defend himself and build your own forces to best exploit his weaknesses.

Likewise, try and be as covert about your unit production as the situation allows, so the enemy must keep guessing. Try to throw him off - it may be strategically useful, for instance, to build but a single flying unit and attack the enemy with it, thus causing him to invest considerable resources in bolstering his anti-air defense in expectation of a full-scale airborne assault. Then, attack for real with your ground forces. Carefully study the unit guide to learn the precise strengths and shortcomings of every unit on the battlefield.

Next: Knowing Hotkeys