Anivia

Strengths

Timing Flash Frost with Frostbite can lead to devastating combinations.
Anivia is extremely reliant on Mana for Glacial Storm. Try getting items with Mana or going for a Crest of the Ancient Golem buff on Summoner's Rift.
It can be very difficult for enemy champions to kill her egg early in game. Seize the advantage by playing aggressively.

Passive · Rebirth — Upon taking fatal damage, Anivia reverts to an egg and is reborn with full health.
Q · Flash Frost — Anivia brings her wings together and summons a sphere of ice that flies towards her opponents, chilling and damaging anyone in its path. When the sphere explodes it does moderate damage in a radius, stunning anyone in the area.
W · Crystallize — Anivia condenses the moisture in the air into an impassable wall of ice to block all movement. The wall only lasts a short duration before it melts.
E · Frostbite — With a flap of her wings, Anivia blasts a freezing gust of wind at her target, dealing damage. If the target was recently hit by Flash Frost or damaged by a fully formed Glacial Storm, the damage they take is doubled.
Ultimate · Glacial Storm — Anivia summons a driving rain of ice and hail to damage her enemies and slow their advance.

A suggested 5-lane lineup built around Anivia, based on hero partnerships and role synergy — not win rate.