As Biondino stated, in addition to reading posts here, posting hand histories will help you tremendously.

another thing you will want to do is use the tourney trimmer - http://www.flopturnriver.com/trimmer/tt.php as that will make it easier for us to comment on your hands.

My thoughts on your above hand history are as follows:

hand 1 - I would have bet the turn for two reasons. First, you will get called and/or raised with a large variety of hands (ESPECIALLY in a free roll) so there is no need to slow play here and secondly a raise shows less strength than a check/raise (which you should have at least done after your initial check).

On the river you can bet more. The pot is almost 1,200 chips. I make it 600 to go.

The next two hands are the same but you made a correct fold against all of that action.