A good flank and aerial enemies can give Pip a hard time that he will not use potions for allies instead for himself. Try use cauterize as well. Resilience also a good counter for his slow and chicken durations.
Pip 1v1s can be one of the oddest fights to come across in the realm. Slows plus using Weightless while facing a wall to give a jump boost should give you an advantage over the enemy. Try to hold off using your heal until you desperately need it.
Pip's ult can turn anyone into chickens. Even if Nando will not Die, Ash wants to fight, Spring has come for grover or you are daring to challenge Makoa. So save your ult if you notice these characters in the enemy team
Pip requires investment. Jack of all trades, master of none. Mega Potion Pip? Put every card you can into Healing Potion. Catalyst Pip? Go for the Weapon or Explosive Flask cards. This will help make Pip's objective clearer to him and his team.
Unlike certain champions, Pip's damage is the same from wherever you fire from or where you hit. Remember to keep distance and practice getting used to the arc of his attacks.