Most of the time the people who bluff and end up wining know exactly how to carry themselves, the game is about trying to deceive and confuse your opponents so that they may think wrongly about your motives.
They are the real experts and knows how to play poker seriously. I'm even afraid to sit infront of those professionals even with just a small money on my hand, they know how to bluff you and they know how to read your face reaction.
If your no good with that then expect that you'll keep on folding your cards and even with the mightiest card you've got, there still a chance that you'll get bluff when they keep on checking and raising. Its true that they are good in deceiving and playing with your emotion but that's a strategy.