What makes a game winning Part 1

I often play games and all I am doing is just developing pieces and trading when it suits me.  I purchased a book by Jeremy Silman called the Amateurs mind and it talks about how you are suppose to win the game by gaining a bunch of small pluses that add up to a "won" position.  A lot of times though there really isn't anything you can do, I don't think...  I mean, for me, it seems like the game is often decided by the other guy, who saw something I didn't.  It's like I don't have any control of what's going to happen.  Some people develop differently than others, and because they developed in a strange way, they ended up finding something to win...  I mean how does one prepare for stuff like that?  I often play the Queens gambit as white and lose a lot of games because I couldn't for the life of me find out what exactly what I was suppose to do, and my opponent, found something to do... and did it!  I'm not going to get into any of my QGD games here, but a game does cross my mind as I jot down stuff here on this blog...  This game I won, but what makes this game winning?  How can one predict an occurance like this, so that one can recreate it?  Here is the game:

I guess the threat of tactics caused me to gain enough of an edge to win the game, but how does one predict that sort of thing.  I mean usually when I win a game like that the game just happens.  Well, it doesn't just happen I did set up a trap that lead to the winning position, but... how does one predict that the game will go in their favor?  Is it all about just making threats, and hoping you will come out better later?  I don't want to hope!  I want to know!  I didn't know I was going to win while playing that game, instead I just concentrated on improving my position, and later won.  More on this later... I want the answer! :D