Fun fact: You’re gonna get raped. I’m talking painful, excruciating, humiliating ass-beating. People will beat you to death with SCVs just because they can. And once you’ve lost every single placement match and ended up in the copper division, you will get raped by hungry scrubs who have watched a few pro replays and kill you dead with cannon rushes, early Reapers, and 6-pool zerglings
Here’s what you have to know.
Playing Terran? Block off your ramp. Just do it. A barracks and two supply depots should work fine–you can lift off the barracks or lower the supply depot as necessary. If you don’t block off, your ass will be owned early on–marines can’t really hang against zerglings or zealots without some kind of fortification.
Spend your money fast. Money in the bank is money that isn’t winning you the game. If you have more than 300-400 minerals on hand, you’re not spending fast enough.
Keep an eye on your opponent. Scout the living shit out of your opponent. Send an SCV out to look for him maybe a minute into the game, and check up on him periodically. Sacrifice overlords, build observers, use comsats–just do what you gotta do to know what he’s building before he kills you with it. Don’t be that guy who goes mass zealots and loses to a single mutalisk.
Key term: “Macromanagement” or “macro”. This is all the stuff that falls under building your army up. Your skills at maneuvering your army don’t matter if your opponent’s army is 3x the size.
Build more workers. Workers give you money. You need money to make an army. Constantly build workers. If you think you have too many workers, build an expansion at another mineral patch and send half your workers over there, and continue building workers from both Command Centers.
Build more supply depots. All the time you spend waiting for your supply depots to build so you can build more units is time your opponent is, well, building more units. Don’t give him that.
Build more barracks/gateways/whatever. The more unit-production buildings you have, the faster you can rebuild your army. And they typically don’t cost much, either.
Don’t worry about towers. Towers are great, except they can’t move, and no dipshit is going to walk his troops in the way of a photon cannon when he can walk around it. Most of the time, they’re not going to help nearly as much as the stalker or whatever unit you could have built instead. Bunkers and Spine Crawlers are a bit more useful because you can salvage them or move them around, though.
Use the back door. Your guys will get killed going in the enemy base from the front. Use dropships/Nydus Canals/warp-in/whatever to get your army in a favorable spot, or use highly mobile units to dictate where the fight happens.
Key term: “Micromanagement” or “micro”. This is how you control your army to maximize each unit’s battle potential. Don’t worry as much about this until you’ve got your macro down. As long as you’re not walking into turret fire or getting owned by units on the high ground, you should be okay.
Build a detector. Observer, comsat sweep, Overseer, whatever. Build a detector that can move, so you won’t get totally owned when your opponent builds ONE unit that can cloak.
Start every game with “gl hf” (Good Luck, Have Fun) and end every game with “gg” (Good Game). Just do it.