This guide will show you the fundamental of counter attack using Terran race when playing against Zerg and Protoss. Here is only an overview and summary of the Terran counter units guide.
First, I will show you how to play against Protoss player. The first thing you must look for is the zealot and stalker combo. Good Terran unit counter for this is the tank and thor combo, put few marines in the front to protect the tanks. If your enemy use colossus or immortals, you can use thors to take care of them because the colossus is not good at doing damage to big units. For the immortals, you will need to use marines or maybe with some hellions. Avoid your tanks and thors from attacking the immortals or you will lose them. The last thing that you may anticipate is when your enemy use void rays. Just use your vikings to deal with it. Create a few of them and you will able to handle the void rays.
Second, you may playing against a Zerg player. Your enemy could throw many different units at you and zerglings attack is one of them. The best Terran counter unit for handling this kind of attack is the hellion, because it will do great damage to the groups of ground units like the zergling. The other Zerg's attack is combination between the roach and hydro. You can use the tank and thor combo to deal with them. It will destroy the Zerg attack. Beware with mutalisk attack. Just use the marines and vikings to take care of it.
If you follow this guide, you should have greater chance to beat your enemy even an advanced player that challenge you in the game.