Jarvan IV vs Xin Zhao

Plant Demacian Standard (E), then cast Dragon Strike (Q) toward it: you fly to the flag and knock enemies in your path into the air.

Land an auto as soon as you reach your target: Martial Cadence (passive) adds damage based on their current health, then only triggers on them again after a few seconds.

Cast Cataclysm (R) on a carry who is away from their team: the arena is impassable, and you can recast to collapse it if it gets in your allies' way.

In teamfights, plant Demacian Standard (E) near the allies who are attacking: it gives them attack speed while they stay close to it.

Get out of the line of the Wind Becomes Lightning (W) thrust: it slows you and marks you as Challenged, which extends the range of Audacious Charge (E) on you.

If you have CC, use it during Three Talon Strike (Q): without his three autos, there's no knock-up, and his other cooldowns don't go down.

After Audacious Charge (E), keep your distance: it's his only dash to get back on you, and without it he has to walk up to you.

After Crescent Guard (R), don't hit him from range: for a moment, he ignores damage from outside the swept zone. Back off, or hit him from inside it.

If you survive his first minutes, play for time: Xin Zhao is strongest early on, through his ganks and skirmishes.