It is always a good thing to amass chips. When an opportunity arises to bluff a pot, I say take it...usually. If you are a beginner it is important to know that decisions are not black and white.
In tournament play, there is a sort of sliding scale to consider as the game progresses. You may have heard that in the World Series of Poker, the first day is about survival—meaning you should keep the super-aggressive play under control until the tournament matures. The idea is that the risk of getting knocked out at low blinds is not worth it unless you have the nuts or an awesome read. On the second day you can start working on your chip stack to put yourself in the position to win.
In single-table-tournament play the same strategy applys—only smaller. I find that most on-line tables under $50 buy-ins are inhabited by weak players, and many high-stakes table are as well. Often, I will make it to the last four players even if I only play a hand or two...or none! Granted only the last three are in the money, but that is only one more player to knock out and your strategy should change short-handed anyway.
It is because of these experiences that I try my hardest to not commit to a pot early on in the game. In a young tournament I tend to not rasie as much with my AK pre-flop, or call a large bet with a mediocre hand against an unknown opponent, and I never over-bet the pot. I survive, let the fish eat each other, then make my move. Typically they will be on tilt by then anyway.