Well, it depends by your type of strategy as i said earlier. I advice you, as i assume you're in bronze, or silver, anyway, a low division, to try rushes. Let's say 11SCV-Supply-2Barracks simultaneously(you'll have the minerals)-While building barracks, make 1 scv then 1 Rafinery and put 3 scvs. you'll make kinda, 6-10 marines . that's the time when you'll attack. Before attack, develop Tech Reactor on one barracks and Reactor on the other, than research to StimPack first. And the show can go on . Be creative. Another tactic that i used while playing terran and caught very well was, the same sh*t without rushing, just training marines, and after stimpack i made 1 factory. Be asure you have the necessary gas. After , make a starport, and at the same time, make reactor on factory. They'll finish at the same time, lift off the factory, and put the starport instead of it. And you make double medivacs without waiting for the reactor to build. Anyway, Starcraft as funny as it sounds is a tricky game, and you can't just learn tactic as poems . You have to feel the game to develop your own style of playing. You can also try 2v2, to see other players style, and then mix them.