PROS

+ You have a really strong early game with Xin'Zhao.
+ Xin'Zhao has a good gank potential since you can easily jump on your opponent which always comes good especially when the enemy has no flash then it's a free kill but if he has flash then he will burn it and you can regank.
+ With Xin'Zhao your 1vs1 potential is very high, because his kit is pretty much made for 1vs1, there are not many champions that match his 1vs1 potential.
+ Xin'Zhao has quite a good scaling even though the champ is made for the early and mid game, he can still be useful in the late game.
+ The champion itself is designed for players who are starting to play jungle and are beginners but that doesn't mean it's bad for higher elo/skilled people, quite the opposite the champion is easy to master for everyone.

CONS

- He's really week vs champions that have stronger frontline, for example Jax, Jax can counter Xin'Zhao because he blocks the main damage from Xin, his autoattacks.
- If you fall behind in the early game, then it's hard to comeback as Xin'Zhao since your champion is made for the early game.
- In the late game Xin'Zhao can be useful with his knockup (Q) and hitting his W, also you can use your ultimate to lure in the AD-Carry.

Gank

Start of by choosing the right path, you try to appear behind your enemy that you can use Q first and walk trough them and with doing that you keep your E for the moment that they use Flash, but not always, just go on a lane use E > Q and if enemy flashed before your last Q depends on their position you can instantly flash too or simply let them go, flash still worth. Keep in mind that you can always regank the lane if he just burned his flash.