Today, I'll be talking about scouting. When and where to do it, what to use, and most importantly, how you react to it.
You will always want to scout at the major time marks.
1) After your 9 pylon/supply depot/overlord. This way, you can check out for cheeses (ex. cannon rushes, 6-10pools, and 2raxes).
2) At 6:00. This is the point where zergs most likely have an expo and pool (maybe even a roach warren for roach rush),
terrans will be finishing either 3rax or an expo, and protoss will either be attack with 4gate or starting colosseus tech.
3) Whenever you expand. Aside from the natural expansion, every time you expand you should scout where their army is, and attack one of their bases. I.E., in PvZ, Ill attack the zergs 3rd, then take my own 3rd at about the 10 min mark. Something like that.
4)What you use: Toss: Basically, as toss you want to use an obs if they do not have detection. If you are doing a heavy gateway build, hallucinate a pheonix from a sentry. If you are doing a stargate heavy build, use a pheonix. Zerg: As zerg, use overlords at the beginning (they have no anti air at this point), an overseer midgame (it is quick enough to escape), and changelings mid to lategame. Changelings are the units overseers ca produce to mimic enemy units. Terran: Terran is a tad easier. Early game you just use scvs, and after orbital command is finished just scan at the major time marks listed above.
5) What to look for: Terran: Look for positioning of enemy's units, so you can do a double pronged attack (small army where their army is and slightly larger drop in the back of an expo). You can also look for unit comp. Ex) Heavy zealots mean you should get ready to micro and get early upgrades and stim. Heavy colosseus means get vikings (2 for every colosseus) and so on. Protoss: Mainly look for expansions and unit comp. Protoss is meant to harass until your turtled deathball is complete. IF they dont have detection (from scout), send some dts in. If they have no anti-air, send in some pheonix/voidsrays. Army is in one base? Drop in another. Zerg: Generally, all you need to scout is army position and structures. If their army is mid map, commit to one of their bases. If they counter-attack, since you are zerg, you will have macroed greatly and (hopefully with good micro) win. With structures. you just want to know if they are gate rushing, archon toiletting, and/or getting early coloseus. Tihs way you can prepare with roaches, infestor/broodlords, or corruptors (respectively)
That concluded my tutorial for today, April 5, 2012.
If you have ANY questions, please just post a reply or drop me a VM/PM.
If you have recommendations on my next tutorial, just PM me and make the title "SC2 Tutorial Recommendation."
Alright, see you guys tomorrow and have a wonderful, cake-filled day.