Blind stealing his my number one tip. Either raise big or push with a decent hand in late position. Also defending your blinds is a big part of my deep in tournament strategy. If someone raises and it is folded to you, you can pretty much call with any hand because of the chips you already have invested and hopefully make a play on them as they most likely didn't hit the flop. This might not work in a freeroll setting as most of the players will play extremely loose. Good luck!