What is the best strategy for playing against an aggressive player in a poker tournament?
Be patient, there is no use playing back into them by raising their raises, because they will immediately shove all-in showing no fear. I was involved in a Tournament where a player was being overly aggressive and was taking players out with absolute garbage hands, Shoving all-in with 8/10 off suit and hitting straights or flushes, He was just a Lucky SOB!
He even started to send offensive messages in the chat box and I found the best way to deal with him was to ignore him, which of course got him mad and frustrated to a point he was all-in on every single hand, regardless of what cards he had.
I was dealt Pocket Aces at one point and thought damn it, I know what he will do if I raise, so let him do it, Win or lose I will see the back of him, So I just limped in for the Blind size and he Shoved as I expected. My aces held up and I doubled my stack, Immediately on the next hand I was dealt Pocket Kings and did exactly the same, Limped in and he shoved, Kings made trips and it was goodnight from him.
Give them enough rope and eventually they will run out of Luck and hang themselves. Just be Patient!