First never (COUGH COUGH) bluff in 10 player tables. Someone always has a good hand.
Now if you have a flush or straight draw then of course you are not really bluffing as much if you bet.
If you end up heads up or in a position you think the other player has notta then this is how bluffing kinda works.
The flop is Q 10 7, and you have the 10. Is it bluffing if you bet the 10 as if it is top pair. What are the odds
they have the queen or better. In a five hour tourney though this kind of bluffing will bite hard when they show AA, KK , etc
If you have A 10 or better in a position to steal large blinds why not bet 3X BB and hope they fold. They will fold more often than not.
I probably am not explaining it well, but sometimes you are betting against what they may have as well as what you have.
Try to call a lot less and sit out more. If you dont make a flop fold. Try to not bet top or second pair unless you think you are bluffing.
If you get low stacked you should try to double up by pushing all in before your stack is 4-5X BB or everyone will call you. You stand a 33% chance against AA, but if you are up against 3 people your odds are much, much less. Try pushing (means all-in) with ANY pair (22 beats AK more often than not) or Ace-rag (preferably above 8), and you might double up.
No matter how low your chips go you are likely onl 3-4 double ups away from chip leader position so don't worry if your pot sags a little.
Only play good cards. Limp in with suited connected cards (8-9 diamonds) or small pairs, and if you don't make a cheap drawing hand or set then fold. If you are aiming for a high pair and have AA, KK, JJ or whatever, bet high before flop to eliminate competition. You don't want someone calling in with 7-2 and getting a boat on flop. Protect your hand.
If you want to draw but are afraid villain may bet too high control betting by betting low. Bet 40 or something and put them in a calling position. This is a good strategy to keep the pot affordable when drawing (i.e. attempting to get a flush, or straight).
Fold Fold, Fold, Fold. Do not accept or play trash cards fro the dealer. Trash them.
Newbs don't often realize the importance of the button, but simply calling in when the button is yours then you can bet if everyone checks and often steal the pot. Position can be as important as cards in many cases. You will realize this when you don't make your hand you called in on from early position and make a poor bet or check to the button who may really have a hand. Position can be as important as the cards.
As I am typing this I just finished 4th in a 27 player. I was first place, but flopped a 10 high pair and lost half my chips to someone with bullets. Least it was in the bubble/ITM.
When you get to top three (OP professed problem area) the game changes. Blinds are sometimes so high that all-ins are almost mandatory when you get pairs, or Ace-J or better. Do not be afraid of all-ins and maybe even practice by playing a few tournaments where you
a) Always go all-in preflop (you can score well in tourneys sometimes if you choose wisely.)
b) Be overly aggressive
c) Be overly tight
d) Fold good hands and bluff a few games.
Try different methods of play. We can tell you what works, but try to get experience. i.e. drawing on a straight sounds good in theory, but it is a statistical nightmare.
If people try to steal your blinds. Let them, but if you have a good hand or think they tried it too many times lately then push back.
One thing is also to look at the pot. dont bet $400 to make $60 if your hand is iffy. There is something called pot odds
which is an advance guide for calling rules. It is sometimes worth limping with a 7-2 into a pot if 6 others have gone in before you. If you do make your hand you will get a great payday.
Patience is the name of the game. Great hands will find you.