All these guys are dead on. A hard working guy who keeps his mouth shut and has a good attitude gets the nod every time. You have to pay your dues, earn the trust and respect of your supervisor or boss. Things aren't always going to go your way, but you get over it and move ahead with a good attitude. If you do all this, your time will come for two reasons. First, because, as these other guys have said, good people are hard to find, and sooner or later, it happens for them. Second, because other people are going to come and go, and a slot will open up. Wen you get the chance, ask for your shot.
If you are a laborer now, and you leave for another company, your going to start there as a laborer too. If a year or two goes by and you haven't had an opportunity, then maybe you should think about moving on. But if we're only talking two or three months, then settle down and be patient.
Bottom line......you gotta pay your dues.