I have a problem that when i participate in a freeroll tournament i cant get to the final table. 

i usualy play tight in early stages in the tournament and later on start to play a bit more agressive

am i doing something wrong. when i get more agressive i tend to lose lots of blinds.

like earlyer today could not paly for like 20 hands  best hand i got was A7 ofsuit

ewen if i get a decent stack I lose it realy fast and then become stressed because i need to win a few pots as blinds increase  any tips on that

P.S. I do apologise about my terrible spelling. Im not english.