Against gangplank, Try to shut down Gangplank early with the help of your Jungler. Gangplank will eventually outscale you in the progress of the game, so putting him behind will make it harder for him to take over the map.

Don't engage with melee trades when Gangplanks Passive is up. It will help him win trades, so wait for him to use it on a minion before looking to fight.

Wait for Gangplank to blow up his Barrels E before looking to fight. If he has one placed in a nearby bush or has one under him, wait for it to blow before looking to fight.  Against gangplank, Try to close Gangplank early with the help of your Jungler. Gangplank will eventually overtake you in the progress of the game, so putting it back will make it harder for him to take control of the card. Do not engage with my trades when Gangplanks Passive is in place. He will help him win trades, so wait for him to use it on a minion before trying to fight. Wait for Gangplank to blow up his Barrels E before trying to fight. If he has a placed in a nearby bush or has a under him, wait for him to blow before trying to fight.