Hey. It has been a while since I wrote my first guide and i gained more and more experience, i have focused in Xin Zhao lately and i thought to my self, why not write a guide on him.If you like this build please rate it and give me a comment, however if there is something you don't like about this build then please tell me either through pm or on the comment section, it will help me with future builds!

Lets start briefly on the pros and cons.

Pros:

-high damage (early and late game)
-Really fast at destroying turrets
-High attack speed
-Effective against off-tanks
-Good Farmer (fast jungle/minion farmer)
-Best for defeating AP Casters with low resists (very fast)

Cons:

-Can be a squishy target early game
-Countered by exhaust and stuns!
-Can Get difficult against champs like Darius [(true damage, high hp,)early game]

Tier 3 Runes can really help early game which is probably why everyone uses them ;)

So for marks I have Flat Armor Pene, however you might want to consider Flat AD marks.
I chose Armor Pene as it will go nicely with the black cleaver.

Seals are Flat Armor, this is standard I would say as without armor a champion like xin will be more like twitch early game (very squishy) especially if you start with boots of speed.

Glyphs, Flat Magic Resist this helps you early game against any strong AP champs.

Quintessence i chose attack speed however, if you consider building two phantom dancers [explained in the items chapter] these runes will be useless to you and if so then i would recommend either AD or Armor Pene.

In this chapter i will tell you about my build and why i build like that, and also will consider some slight alternatives which may (in your opinion) make the build better.

Okay Twisted Treeline, I start with boots of speed, 2 health potions an a mana potion. I like starting like this because you consider chasing someone on 'first blood'. You could start with a dorans blade this is a good choice, it gives you damage and health but i think the starting items are probably a matter of opinion :)
I usually play top as xin (depending on my team) and i upgrade to berserker's greaves which keeps my MS high and also gets my atk speed greater, then i but cloth armor (asap) as this keeps you safe from being extremely squishy, then madreds razors and (helps with dealing with dragon and also fast minion farming) straight after those i get phantom dancer ASAP as from then you should realize what happens (dmg). The next item is your choice its either the recurve bow or the pickaxe (this really depends on oppinion however in my opinion xin him self has good damage therefore i get the recurve bow). Madred Bloodrazor, this may seem a little wierd for xin zhao however the damage output is amazing and also makes farming and dragon killing so much easier (for xin). Now I get a Vampiric Scepter as it can really be usefull with the passive of xin's W, From here its actualy your choice which one of the three items you will build. Personally i build bloodthirster 'most of the time' however lately i have been building the black cleaver first (which makes the dmg output really sweet) however the infinity edge i would not recommend as a first item after madreds simply because you dont have enough AD for good crits. And that would be it from the build i have suggested for you!

Alternatives!

There is probably two alternatives i could think of
1: instead of infinity edge buy a second phantom dancer however then you should consider changing quintessences, a second phantom dancer goes really nice with madreds and xins 'W' because you will get over 2.3 atkspeed (lvl 18 2.5 i think) and with the black cleaver the crits get high!
2: instead of madreds a second bloodthirster, i dont recommend this but if you are simply owning and you have alot of money then two bloods and infinity edge make your health high at all times.

Briefly here:
Max Q whenever you can!
this is because xins Q is the highest dmg skill that xin has and also just after jayce/zyra patch Q can be used on turrets!

I max E next because it slows the enemy which is what a 2.5atk speed xin needs ;)
Then the W spell maxed last because if you get bloodthirster after madreds then you dont really need that passive.
Ultimate maxed as usual at 6,11 and 16

If you play offensively and very aggressively as xin (like i do) then ghost ignite are the best spells to choose because the ignite can be used either as a debuf or a killer (last dmg blow) i usually use when my target has about 1/5 of their health and then try to deal as much damage as possible and also turn on ghost to chase him (ghost with a phantom dancer and berserkers have a very fast output)

If however you are more of a defensive turret hugger like some of my team mates then consider flash and then either ignite or exhaust (where exhaust helps you to either chase or stop someone chasing you)

In general Xin is very fun to play and deals tons of damage through out the game, he is a very good champion in team fights as he can group slow and also knock back and up!
Hope my build and guide is understandable and please leave a comment when you rate :) it means a lot to me and it inspires me to make further guides.

cya ;)