Thats a classical build but... Hydra ? Yes hydra and ruined king its very good at xin cause the steal life and attack speed help us in Q and W. And xin is a great tean fighter so hydra will help a lot cause u have damage but u are tanky with this build too. You can also have a tabi ninja instead of mercurial if they have and AD mid , jg and top. If they have a jax top i prefer mercurial but if they have a renek and a yasuo mid i recomend tabi. U can also rush a banshees veil innstead of sunfire if they have very much AP like a ryze top and a veigar mid. This is my favorite xin build off tank coment if u want a full tanky or full ad or maybe full ap lol.

Max Q Then W and finnaly E and max R when u can. In JG start with W then Q then E and then max like i said.

In runes i use marks of AD seals of armor and gliphs of magic resist quintecenses of AD or attack speed are great in win xhao.

A 21-9 its good. But i preffer tanky with a 9 - 21

Start with blue and then red. Use W when jungling.

Excelent early and mid game.
Hard CC
Movement
Nice at the moment of starting team fights
Its from demacia.

Cons

A champ who has a jump like kha six jax or tristana can easyli scape from xin powers
Doesnt have a form of scape like tynda's or renek's E
Jax will destroy u evading ur Q and W combo D:
.

Xin zhao is very good when we talk about starting a team fight. I usually E in the middle of the team, throw the active of the randuin then R and throw the active of the ruined king to the ADC then W , Q the ADC and kill him. Then when the adc is dead u usually have to focus the mid . Always left to end the tank and the support.Talk with ur team about focusing in team fights. If u want ur third blue can be of the AP MID u dont really need i that much.