Ancient Apparition

Make maximum use of your high attack range and Chilling Touch to harass in the lane without aggroing lane creeps.

Use Cold Feet when it is likely to stun, for example, after your laning partner applies a disable or slow, or just before the opponent wants to last hit a creep.

Ice Vortex can be used to provide vision on top of pillars or in Roshan pit.

Prioritize Ice Blasting heroes high on healing and with big health pool.

Grab Aghanims Shard at 15 minute mark as it gives you a massive area of effect stun with Ice Blast.

When not much is happening on the map, use Ice Vortex to farm creep waves without showing yourself.

When Ancient Apparition's Cold Feet is used on you, move away 715 distance or you will get stunned.

Ancient's Ice Blast negates all healing. Avoid using healing items when affected by it.

Ice Blast goes through spell immunity but is offset by magic resistance and magic barrier items.