Kill the egg quickly when Anivia dies — she comes back with a decent amount of HP if you let her regenerate.

Her Q is slow and predictable — dodge it by walking sideways and she loses half her burst (no double damage E).

Anivia is very mana-dependent — force long fights to drain her, especially before she has her mana item.

Punish her before level 6: her waveclear and zone control are much weaker without R.