Attack speed, crit, movement speed, lifesteal and DMG, makes Xin Zhao a very quik and overpowered champion in both 3vs3 and 5vs5 games.
Try this out and give me feedback.

If you get in trouble sometime, just use ghost or flash to make sure you will survive another strike against one or more enemies. Make sure someone in your team use exhaust to slow them while Xin attacks with his overpowered combo-strike.

As you can see, my masteries makes his cooldown shorter so he can waste his ultimate for farm. With this build i usually get 150+ minion kills.

Xin deals surprisingly much damage. With theese items, there is no escape for your target. Tanks can be hard to take down with one combo attack, but divide the strikes so you can easily take dowm your target when his health points is low. You can actually amaze them by being so quick.

In late game when you have bought all items, sell your boots and buy another Infinity edge or Bloodthirster.

Pros
Ganks
Easy escaping
Fast assist(when teammate needs help from another lane)
Sololane

Cons
Midlane
No stun