But after reading this guide, i finally understands that the problem is not my micro or what i build to counter the opponent, it was actually my macro, and the ability to replenish my army after a big battle.
I tested this in my game right after i read it... i had 3 expansions and 4th coming on, 8 barracks with a big game plan of marines backup by 2 factories building tanks. And i won easily vs zerg that had a ton of banelings(which i hate most). Yeah my marines died but i just kept coming back. :)