Strategy guides
One standard strategy per matchup, from the why to the build, with what to do when you scout each thing. Written for every level; if you are new, read the first three sections and stop there.
You play Терран
Mech
TvTТерран vs Терран
Siege first, expand behind the line, mine and drop to make them move, and never attack a sieged tank line head-on.
Mech
TvPТерран vs Протосс
Siege-expand, mine the map, keep vultures and tanks streaming from three factories, and take fights only where your tanks are already sieged.
Bio
TvZТерран vs Зерг
Take two bases, build more barracks than feels reasonable, keep marines and medics streaming, and make siege tanks the moment you see lurkers.
You play Зерг
Three-hatch mutalisk
ZvTЗерг vs Терран
Three hatcheries and drones, mutalisks to keep the marines home, lurkers to hold your bases, and defilers with plague and swarm to win the late game.
Three-hatch hydralisk
ZvPЗерг vs Протосс
Three hatcheries and drones, hydralisks with speed and range to stop the first push, a fourth base behind lurkers, and hive tech before Protoss has its third.
Zergling and mutalisk
ZvZЗерг vs Зерг
Match their zerglings, get the spire by 4:00, keep mutalisks alive with scourge behind them, and never let your drone count fall behind without a sunken to justify it.
You play Протосс
Gateway macro into arbiters
PvTПротосс vs Терран
Expand faster than Terran, keep dragoons and zealots streaming from many gateways, see the mines with an observer, and win late with arbiters or carriers.
Forge expand
PvZПротосс vs Зерг
Forge expand behind cannons, corsairs for overlords, +1 speed zealots with templar at 9:00, and the third base behind that attack.
Dragoon and reaver
PvPПротосс vs Протосс
Two gateways of dragoons with range, a robotics facility for the observer and a reaver, then expand and out-gateway them.