For Terran, I usually follow a path of two techs-I'll rush in bionics with three/four barracks running, while building 5/6 factories. If it is possible, I'd follow up with a few vultures with mines, as vultures are surprisingly good against early units and laying mines before hand and luring enemy units with the ruse of retreating are also surprisingly effective. There's a 50/50 chance that this will succeed, hence the construction of factories. Heavy mechanics are key for any race, and even zergs will melt against mechanics, with only a few vulnerable siege tanks and many goliaths and vultures. Building huge numbers of factories is key, you'll find that you micromanage your units too often and find not enough time to produce units or macromanage your economy, eventually leading to huge stacks of resources. I also have 2-3 separate forces instead of just 1 main force as many players do, as reserves to send or strike at weak points.
And he said to Saint Peter "One more soldier reporting for duty, sir. I served my time in HELL"
Now we just need "Proud South Carolinian" to ask for advise on how to be better at NASCAR, "Proud South Central LA" to ask for advise on how to be better at basketball, and "Proud South American" to ask for advise on how to be better at soccer and we'll have all hte ironic stereotypes fixed.
I'm really good at Nuking enemy bases. If the Zerg have large areas of Colonies I increase the Ghosts' sight range and Nuke. I always play CPU though so with a person it might be different. I've never heard of the all-Zergling strategy. I know that Zerglings are good to use at the beginning to take out a player early on. If I can get Siege Tanks and am able to upgrade the power of Infantry Weapons I can usually handle Zerglings. If someone uses that strategy I would need lots more Tanks. When I play I normally focus on the defense a lot, and if I can get a Nuke Silo and Battlecruisers with Wraiths I can manage an attack. The way I play though I need to be able to access resources in order to maintain my defense.