First thing you do is make 7 scvs. Next u use one of them to make a supply depot. Then as that is being constructed make 3 more scvs. When the depot is done make a barracks. While the barracks is being constructed, make as many scvs as u can plus one more depot. When the barracks is done make four marines. While u are waiting for them make 2 bunkers at the area(s) where ur enemies can attack u. Move two marines into each bunker then make four more marines. Make an Academy and another Depot. Make a Refinery and 3 scvs. When the Refinery is done put the three scvs on it then make another scv. When that scv is done make a factory. When factory is complete, make a machine shop and put the scv (that made the factory) on gas. Save 300 minerals and 200 gas then build two tanks. While u are waiting make a enginerring bay. Research longer attack range at Academy and armor at enginerring bay. Research Seige mode at machine shop and put tanks at defense areas. Build depots infront of ur bunkers make sure THAT U STILL have a way to leave ur base DON'T lock yourself in. Make missle turrets around ur base to keep out any flying guys the enemy might have.

ANOTHER STRATEGY:
-Put all SCVS to work

-Build scvs until you are 7/10 supply

-Take your 7th scv to build a barrack (build in middle of choke point at all

costs, if you do not have one build near your command center)

-Build scv and use 8th scv to build supply depot (build beside the barrack at choke point, otherwise build near CC)

-when buildings are done, put both scvs back to work again and pump out marines one at a time.

-Build another 3 more scvs

-When all three are done, take one to build another supply depot.(again at choke or near command center)

-Build another scv and use it to build another barrack, this time wherever you want.

-Build another scv and build bunker, do this twice.

-Once the buildings are done put all scvs back to work again, keep in mind to keep building marines. At this point you should have enough to survive almost any rush. Remember if you do not have a choke point, build all of your buildings close to the command center. A tight base should give your enemies a hard time to destroy you. Keep moving up the tech tree, and building scvs!

ANOTHER STRATEGY
First, u need to to get your four SCV's mining and with the 50 minerals u have get another SCV keep on doin this till u have 10 miners, then u need to build a Supplies Depot, make two for good measure, then get more more SCV until u have 15 miners, then build another Supplies depot, and get 4 Barracks Then buuld a refinery make more SCV's to get gas, then make an Academy then keep on mining up then in 1 Barracks Get Marines, then next 1 get Medics, next get Firebats, and the last 1 make a mixture of all of the them u need alot of medics if u r fighting protoss or terran.

A GOOD STRATEGY
Do these steps AS QUICKLY AS POSSIBLE FOR MAXIMUM EFFECTIVENESS!!

1: set all SCV's on the mineral patch, produce another with the 50 minerals at start

2: set that SCV on the patch, when you have 150 minerals mined, build barracks with one mining SCV

3: build another SCV as soon as possible, when he's done, you should almost have 100 minerals for a refinery.

4: build refinary and another SCV.

5: your barracks should be done, when your refinery is, set 2 SCV's on it. Build factory with the SCV that built barracks.

6: If you want, you can put another SCV on the refinery, either way works.

7: build starport when you have enough.

8: build science facility and covert ops.

9: get silo and depot

10: build academy while silo is arming.

11: start pumpin' out ghosts and have fun!!

12: when you have enough, you may want to build extra silos, I usually have 4 or 5 by 20 minutes.

If you do this right, you will be short on minerals and will wait a lot. It seems slow, but keep with it and it will build up in no time. I have won 16 straight games with this tactic. Also, if your being attacked and you know you won't make it (and have a partner), commit suicide by nuke to help them. It's better then just dying and not contributing. If you have a partner, ask them to send you defense so you can concentrate on just nukes. If you have to worry about defense, put bunkers with a 3 marine, 1 firebat ratio in your chokepoint. Back it up with siege tanks. While it won't repel big attacks, it can buy you time to lift and find another spot. This works well if your partner is late with defense for you, 'cause then you can land in his base and destroy alot of his Defense!!!

ANOTHER STRATEGY THAT IS PRETTY GOOD\
Make 7 SCV's whit the 7th one build a supply depot then while the supply depot is builded make 2 SCV when the first SCV is done the supply depot will be done too build one barracks whit the same SCV that was building the supply depot while the barracks is getting builded make 2 scv and build one refinery and put the other scv to harvest gas when the barracks is finished make one marine and one SCV to harvest gas. wait until you have 200 minerals and 100 Gas (not much time) whit the scv that was building the barracks build a Factory In like 20 seconds you will be able to build another, get one SCV that is getting minerals and build it (the factory) when the 2nd factory haves 50% done, build the Add on to the factory and research Siege mode While researching siege mode you will be able to build a tank and build the add on to the other factory. in that time try to make some marines like 6 so the tanks have some support. Build 2 tanks more and then build the academy while building the academy you will have like 5-7 tanks send them whit the marines to look for the bas of the opponent (if its a 1 vs 1 map it will be more easy. When the academy is finished build the add on for the comand center (comsat Station) you will be able to scan one time (whitout waitnig) when you found him scan his defenses (if he have some) and pleace you tanks in siege mode, that makes the opponent get Mad when you destroy his defenses get back to tank mode the tanks and send them whit the marines. The enemy will be inoffensive against you (if you do it correctly)