Alistar Counter Tips
As an ADC don't stay too close to enemy tower if you don't have flash because Alistar will try to flash-combo you which will result as easy kill for enemy team.
When facing Alistar as an ADC never stay next to your support because he will push the support and kick you up in the air.
Alistar spells have high cooldown time, missing his combo is a chance for you because there is nothing he will be able to do in the next 7-8 seconds.
Alistar has low mana amount and forcing him to do few sequenced heals will cause him to run out of mana and since there are no mana potions anymore it is easy lane for you.
Due to his really high defensive and tanky ability Alistar should be the last one to focus in team fights.