To pull off this strategy, first you must get enough resources. You are probably a newbie if you don't get at least 25 workers to mine minerals at money maps such as 0 clutter or fastest map ever. Always build scvs, until you think you've got enough resources. Do no build defense unless you really need to. If you don't build defense, go strait to factories. Get about 12 factories and like 6 starports or something, to produce dropships. Don't create to much dropships, as they do take up 2 supply of your 200 limit. Always upgrade tanks armor before weapon. The tanks do hit an 85 when fully upgraded weapons, but it wont survive as long as a 4 armored tank takes beatings from marines or any units. Get science vessels and goliaths as well. Scan around an opponents base then drop the tanks near anywhere that is safe. But best place to drop is where you opponents workers are. After you kill their workers, they would probably get really weak. Massive tanks really mean massive tanks, go about 30-40, because of the dropships supply. When seiged up, tanks cause havoc even when 12 battlecruisers are attacking your tanks. Tanks kill incredibly fast.
Goliath / Wraiths
Goliaths are useful for attacking large air units, if they have battle cruisers, carriers or any other large air units, get a lot of golaiths. Goliaths got a fair ground attack also, use goliaths to attack your opponents base with wraiths to attack your opponents workers, nexus, command center, or hatchery, and cloak em' just in case. Always scan, if they got some air defense, and you don't have enough wraiths, you'll get killed. Its always good to attack from two or more directions. Its good to use about 8 factories or more to produce goliaths and 6 or more starports to get wraiths, if you got the resources. On money maps, you should get more factories and starports.
Attack an enemy with a lot of units. Don't use marines or anything, they will get killed fast. When your units are attacking, your enemy will probably be distracted and attack your attacking units. If they do, load up some ghosts and drop em' behind enemies mineral fields. Then nuke their nexus, command center, or hatchery with 2 nukes. If they are protoss, you could just emp their nexus and nuke once.
Countering A Bunker Wall Defense
Of course, people would counter a walled bunker defense by going air, dropping, using tanks, or just a massive attack. If the opponent has massive tanks for defense, your only option is to drop or go air. They probably have turrets, so it will be hard to drop. If you decide not to go air, get a lot of tanks yourself. Then, move your tanks, close to the entrance of an enemies. Like in the fastest map, move it out side of the bridge, or where your tanks cant be hit. Next, sacrifice a marine, send it off to get killed. Then, you should see a blood mark left my the marine. Move tanks behind it, where opponents tanks can't reach it. Then, use upgrade ghost or anything to get more range for tanks, because of their 12 ranged attack when seiged. Usually, their other tanks will be behind supply and bunker, if not, this strategy is useless. If they got bunker or a wall, your tanks should beable to take them out. After their wall and bunkers are gone, you can send off your tanks to attack. Then I suggest to try to drop tanks and goliaths. Get wraiths to distract turrets.
Counter Carriers Or Dragoons
A lot of protoss players tend to get dragoons or carriers. If they get dragoons, simply get tanks in seiged position, even a number of 20 tanks could kill alot of dragoons. With their extra long range, damage, and splash damage, tanks could almost kill all ground units when grouped up. And when countering carriers, in a open field, goliaths are the units to get. But if you don't want to, try using battle cruisers with the amazing yamato cannon to take out a few carriers. Emp before using yamato cannon. Also get defense matrix, and always attack the carriers. I suggest you command 3 squads to attack 3 different carriers at a time. Or more, never attack interceptors. Either get bcs or wraiths. There is not that much units that can counter carriers along with corsairs though. But then again, bcs and goliaths can run them over.
Countering A Massive Force Of Guardians And Devourers
It will be hard to counter them, because guardians will be best killed by terran air, but the devourers can kill the valks, bcs, and the wraiths. A lot of newbies would think, that it is impossible to kill em. But you can use a science vessel with irrdiate and kill em all. Or use defense matrix of valks or bcs to attk the guardians, the devourers. Or use massive golaiths force. They can clear up the air in no time, with upgraded missle packs, the got enough range to hit the pesky guardians, and with the golaiths being so cheaper, you can make them very fast in non money map games. You can also get some tanks after killing their guardian and devourers. Never use marines, they usually cant even hit a guardian 1 time. Even with stims.
Pesky ultralisks and mutalisks
I don't really know anyone that uses ultralisks with mutalisk, if they do, get marines and tanks. As simple as that, and have medics. But I personally think ultras and mutas are a good combo. They can attack your workers and when your attacking the mutalisks, their ultras can rush in with amazing damage, armor, and health, but valks or marines can take care of the mutas. And let seiged tanks handle the ultralisk, with the blast of 70 and splash damage effects. Either that or use battle cruisers to kill them both. Both ways are good though.
Terran Tactics - Command the Land
When you've discovered prime territory for expansion, don't just send an SCV out to the site to build a new Command Center. If you have some spare resources and more than two existing Command Centers, pick up and move one of them to the desired location. This way, you can take over part of the map before anyone else.
Terran Tactics - Start Your Vulture Production Early On In The Game
Get your Vulture production going and Spider Mine research completed as soon as you can. Vultures make for great scout units due to their high speed, and they have the Spider Mines going for them as well. Sure, laying Spider Mines is a high-maintenance kind of thing. But it's well worth it--20 or 30 mines laid out in front of your base will create hell for approaching enemy ground units.
Terran Tactics - Battlecruiser Online
In air combat, the magnificent Battlecruiser, with its Yamato Cannon, has to have one of the most powerful air attacks of all the races combined. They can create quite an impact in groups of two or three. In large-scale battles, use them to pick off moderately powerful targets. Make sure you retreat them when they've sustained significant damage--they're too expensive to lose, and the Terran SCVs are handy at repairs.
Terran Tactics - Nukem
Use your nukes against massed troops, rather than buildings. First off, troops that are awaiting battle orders are more frequently unprotected, so your ghosts can get through. And second, there's no better way to soften up your opponent and break his morale than by wiping out or seriously damaging his "killer" battle group.
Idea Of Sience Vessels
If you are a newbie and don't really know much, you should use this strategy. You can't attack, unless you irradiate with vessels. To get vessels, build a barracks, factory, starport, ad on the control tower, then build a science facility. After all these are complete, start building more starports with towers. Get about 20 or any number you feel you need. Upgrade armor for air, and everything for the science vessel. Against the zerg, use irrdiate to their hydralisks or mutalisks, players usually get those two units in money maps. It is very useful to use it against workers, because they are stacked. Bring like 50 science vessels behind enemies base where workers are. Then, launch off the poisonous gases. This really does work, but you wont be able to attack. Help your allies by using defense matrix on your allies, it adds 250 hp for a while. I suggest you at least drop a few marines when "poisoning" their workers. Stimpacked is better.
Nuclear Launch, Detected...
Newbies should learn how to nuke. Here's how, build a lot of command centers, then build barracks, factories, starports, academy, science faculty, then ad on the convert ops. Build ghosts then ad on nukes. Build nukes, while researching cloaking, lockdown, and extra vision. Drop ghosts with dropships and land behind minerals and workers, get science vessels or wraiths to block hits for dropships while traveling, only put 2 ghosts in each dropship, because a lot will be shot down. After they land, press nuke button, and press the hatchery, command center, or nexus, even if you got 18 nukes, just nuke it, because enemies will attack you. And by the way, cloak before doing this. Also have some marines to take hits for ghosts. A nuke landing and killing 40 workers is a sight you really got to see if your a newbie.