Strategies



Strategy is very important in StarCraft 2, without it you generally don't get anything specific done to properly beat your oponent.


Protoss



4 Warpgate Rush

The 4 Warpgate Rush is a very common aggressive opening in PvP, and to a lesser extent, PvZ, or even PvT. 4 Warpgates can provide a constant stream of units that allows the player to put a lot of pressure on the opponent. It is semi all-in since even though the performing player can transition out of it, constant unit production out of 4 Warpgates allows little space for teching or expanding. Therefore, a substantial amount of damage has to be done when using this build; otherwise the opponent will likely have a large economic or technological advantage. The build also relies on the use of a proxy Pylon to quickly and continually reinforce the initial push.

Below is a standard one Gas variation of the build. Other slight variations are possible and sometimes better, depending on several variables such as matchup, the opponent's strategy etc. PvP will always use a one gas build.
    * 9 Pylon
    * 13 Gateway + Probe sent to scout
    * 14 Assimilator
    * 16 Pylon
    * 17 Cybernetics Core
    * 18 Zealot[1]
    * 22 Stalker[2]
    * 24 Warpgate research[3]
    * 24 Stalker
    * 26 Gateway
    * 26 Gateway
    * 26 Gateway
    * 26 Pylon[4]
    * 26 Proxy Pylon 

  1. This Zealot cannot be skipped, especially in PvP. You need a Zealot and Stalker to protect your probe that proxies a pylon.
  2. Chronoboost
  3. Use 4 Chronoboosts.
  4. You will be at 26/26 supply when you make this pylon. This is intended. Probe production should be stopped at exactly 26 supply for a total of 22 probes. This pylon must be built after the 3 gateways, or the gateways will not finish in time.
Notes

Execution






Zerg




Roach Build

This is a common opening strategy in Starcraft 2 Beta, there are variations of this build, but this is the most economical one. The goal is to have a very solid economy for roach production very quickly, yet be able to defend most 10pool and roach openings. It is best applied for ZvZ, but can also be used ZvT versus Marine/Reactor or Hellion/Factory openings as well as ZvP for 2 or more gateway zealot rush openings.

    * 10 Overlord (extractor trick)
    * 15 Pool
    * 15 Extractor
    * 100% extractor 3 drones on gas
    * 17 Roach Warren
    * 16 Queen
    * 18 Overlord (extractor trick) 

Execution

Depending on what the scout(s) see the build can vary. And this build should be avoided if scouting 6-10pool. If the opponent is doing the same or similar build, you may delay the timing of spawning pool or roach warren (based on walking distance).

Upon completion of the roach warren you will usually have 1 free larva, depending on the opponents action you may make a drone or roach here. Shortly after the Queen's Spawn Mutant Larva should finish on the hatchery, again depending on the opponent you may make drones or roaches.

It is common for this build to get lair tech in ZvZ very quickly after about 5~ roaches are created to defend the ramp/choke. 5 is a good number because 5 roaches will do 75 damage in a single volley(after armor reduction) to another roach, and a roach has 145 hit points (2 volleys will score a kill). Once at lair tech, you will need
  • Roach Speed
  • Burrow
  • Morph an Overseer (for detector to keep with your roaches, to spawn changelings to scout, and to itself scout with the speed increase)
It is arguable to get overlord speed upgrade next as well for 50/50.


Terran




1 Rax FE

Focused on getting a very early expansion while there with minimal Marines numbers and Bunkers for defense. This defensive stance allows the Terran to take a relatively safe Early Expansion to their natural, and provides many transition opportunities against all races. By playing a highly defensive early game with a limited number of units, the player secures a very quick economic advantage that lends itself to a highly flexible midgame.
    * 10 - Supply Depot (1)
    * 12 - Barracks (1)
    * 13 - Gas (1)
    * 15 - Marine (1)
    * 16 - Orbital Command Upgrade
    * 16 - Supply Depot (1)
    * 17 - Barracks builds Reactor
    * 18 - Constantly produce Marines from this Barracks
    * 20 - Command Center (2) in-base 


Notes


Early harassment from the opponent is actually ideal. If countered properly the opponent has made a large investment in tech without much on useful army and economic infrastructure as you.

Quickly the early and mid-game will be in your favor as the opponent has nothing else they can do with the tech they have made (i.e. Dark Templar, Blue Flame Hellion/Cloak Banshee, Mutalisk). Being prepared and scouting is key, and will put you a head so long as you are prepared. Tech Lab Opening:
  • 1 or more Reapers for harass/scouting. Will sometimes allow you to immediately place the Command Center in your natural. The Reaper(s) can serve as fantastic scouting and harassment units, helping to force enemy units to stay in their base and scouting any early aggression.
  • Marauders with Concussive Shells for map control and defense against Stalker or Roach pushes, very effective for Protoss in the very early game.

  • Reactor opening:

  • This can be particularly good against Zerg, as it allows for a very defensive position from behind a wall, and if Zergling Speed is not complete, early Marine pressure can be applied.
  • Your high Marine count allows you to defend against many early pokes from all races, and provides the structure for a Marine/Tank composition in the midgame.

Scouting

When scouting, your primary objective should be to see whether or not you need to put down additional defenses (usually in the form of bunkers) at your expansion, as well as to see any early tech choices your opponent is employing.

Execution

  • Keeping your infantry in a good arc is instrumental in holding off early pushes. Bunker placement can also make a big difference - place them somewhere you can repair well but where few of your opponent's melee units can attack it at the same time.
  • Don't place too many bunkers too close together as this can impede your troop movement as well as how effectively your SCVs can repair.
  • Scouting is essential to glimpsing any early aggression or cheese plays you may encounter as well as being able to respond appropriately. Good Marine spread and control can be essential in some situations, such as early Hellion harassment, or Void Ray play.


There are far more strategy's out there, the more you know the better you can do.