Okay, this is my first guide, first one in English in my whole life by the way. I'm Argentinian and I was bored so I decided to try this and show you all how I build XinZhao, in my opinion, a very OP champ when well used.
So here it goes, hope you enjoy and rape many noobs.

Armor Penetration Quintessences: In my opinion, the BEST ones for AD DPS champs. You need 3 of this and you'll rape. You can also take 3 Attack Speed Quint. but I don't recommend them just in this case, this build uses a Phantom Dancer + Xin's (W), thats all you need.

Armor Penetration Marks: More ArPen = More Kills ! (I do love Armor Penetration)

Attack Speed Zeals: This will give you an early game adventage. Useless late game with all that AS amount. So you can get Cooldown Reduction Zeals, up to you.

Cooldown Reduction Glyphs: Xin's ability cooldowns are a bit high, specially early game because you don't have enough attack speed to low them with your (W). (You will notice that, in late game, you will constantly using your (Q) and (E) because of your AMAZING active (W) skill)

I usually start with Doran's Shield. This gives you a nice lanning phase, with more survivability and some health regen so you can stay in lane for a while. If you are confident and you think Doran's things are for Noobs, just dont get it, go for the next one.

Attack Speed boots for some early adventage. Some people usually gets Mercury's Treads because Xin is vulnerable to Crowd Control effects, so it's a good way to get survivability.

Immediatley after your boots get a Black Cleaver. XIN MUST HAVE THIS ITEM; Why?. 30 Attack Speed + 55 Attack Damage + Reduce target's Armor. Do you need more? Start by getting a BF Sword. Then the rest.

(Optional)
For some reason I take Zeal after BC. I think you need more Attack Speed BUT, I get it because of the Movement Speed Bonus. Believe me, from 390 -> To 420 (Approx.) it's a nice amount.

You now may need some more Damage, I'm sure you want to get a Bloodthrister but I have a more interesting offer. Get a Phage in order to get more AD + HP + Slows Enemy Target. If you need even more survivability go ahead and get the Frozen Mallet as I usually do.

At this point you MUST rape at least a Ashe champ xD. You are about to rape even more. Get Phantom Dancer = More Attack Speed + Movement Speed + Critical Chance.

Excellent item for Xin. AD + Critical + Armor Penetration + Cooldown Reduction. You can get this before going for the Phantom Dancer, it's up to you. But this item MUST be in your build. Also for its passive. Extremely dangerous for enemies.
Depending on the situation you may get one or another Item.

If you need some Magic Resist and Armor get it. It also revives you ;O (Recommended)

Just if you want more damage and you are doing fine with your currently armor & magic resist. Also gives you NICE Life Steal. (Bit Recommended)

If their team is too tanky, might work fine.

Armor penetration! Against armored enemies.

JUST in case the other team are almost ALL mages and they have too much CC.

Against DPS teams.

As XinZhao you may initiate team fights, I dont really recommend it. If you have one tank in your team just let him initiate. If you don't you may go in with (E) Audacious Chargeand IMMEDIATELY after that (R) Ult. Crescent Sweep. Using your ult there is VERY important there because it gives you increased amror and magic resistance. A bit useful if you are tanking.

The skills combo is nothing else than use (Q) Three Talon Strikeright before using (E) Audacious Charge. Then (W) Battle Cryto increase your attack speed also lowering other abilities cooldowns. By the time your (W) finishes your other abilities would have their cooldowns refreshed. Time to finish your enemy !

Don't, and I repeat, DON'T WASTE your Ult (R) to kill one enemy, you may need it to get out of an incomming gank. If you are sure that you are not being ganked, feel free to smash that enemy by entering with (E) Audacious Chargethen (R) Crescent Sweep. The reason for using your Ultimate first is because it deals damage + 20% of the currently enemy health.

Thanks for reading this "guide". I'll appreciate your comments.

Comming Soon:
+ Team Work
+ Farming