Scouting Your Enemy Courtesy of Emo from this thread:
http://us.battle.net/sc2/en/forum/topic/375107556 The absolute most important thing you need to do in your Starcraft 2 career is scout your opponent. Here is guide on determining your opponents strategy based on what you find at his base.
Note, Always set some waypoints at the enemies base (hold down shift and right click around their base) so that your peon can keep moving and gathering scouting information. This makes it hard for your opponent to kill your peon until they have some type of ranged unit, and can provide crucial seconds of information. Skilled players may even attack the SCV constructing the Terran's first barracks, forcing them to pull another SCV off the line.
vs. Protoss *Gateway close to finishing, still no gas - Possibly a double gate, means early Zealot push. Keep your probe alive to confirm.
*Fast double gas - Stalker/Sentry from a 4 gate, or a 3 gate Robotech.
*Gateway close to finishing, one gas - Generally a standard 4 gate build. Keep your probe alive to confirm, note when the Cybernetics Core goes down.
*Forge with no gateway - Cannon Rush. Scout in and outside your base for the offending probe and pylon.
vs. Zerg *Fast Expansion before a spawning pool - Macro oriented build
*Spawning pool is almost done by the time your peon arrives - The 6 pool, FAST zerglings (be sure to scout behind the mineral line for the spawning pool, pro players often hide their pool there so a lazy scout would not detect it)
*Spawning pool at a normal time, no fast expansion, gas finishing - Expect Roaches
*Gas after spawning pool has completed - Speedlings and possibly banelings
*Early gas before spawning pool - Also speedlings with possible Fast Expansion (Killa)
*Spawning pool at a normal time with an expansion shortly after - Standard Zerg opener.
vs. Terran *No gas, 1 Barracks finishing, another under way - Mass marines
*No command center - High yield.
He lifted his base off and more than likely placed it at the high yield, or an island base.
*1 Gas, starts building 2nd barracks - Mass Marine/Marauder
*1 gas, starts building a Factory right after Barracks- Expect 1/1/1 build, a versatile Terran build consisting of 1 Barracks, 1 Factory, 1 Starport.
1/1/1 lends itself well to early cloaked banshee harass
*1 Gas, barracks with early techlabs
Reaper rush
*No barracks - Proxy barracks, scout around your base for a nearby barracks meant to pressure early with marines / reaper
**Feel free to add your own interpretations or any that were missed above.
