I play a lot with all check and then one raises even small, they get pot. Is this effective , is this one of the way to get big in tournament with many weak player.

As with everything in poker, it depends. How many players are involved in the pot? It's way easier to bluff one player than getting 5 players to fold. It also depends on your position. Bluffing UTG is generally riskier than on the button. Another aspect is your hole cards. Do you have any blockers which makes it more likely for your opponent to fold to a bet? Those are just a few consideration to take into account. If you notice your opponents are very easy to bluff even with very small bets, then by all means go for it. Just make sure to not become predictable, since even complete amateurs will see through this "strategy". As you face better opponents, this will become less and less effective.