This is an a jungle guide for xin zhao that I have personally found to be optimal for most games I have played with him. I will cover some of the differences in item/rune choices.

I choose these runes because they give you the most sustain/damage in the jungle and during ganks. Armor penetration marks work very well with xin zhao's passive and give you a lot more damage to help secure kills. Armor seals help get through the jungle while taking less damage from creeps. Magic res per lvl is great against the champs with a lot of burst damage like le blanc or cassiopeia. life steal quintessences give you even more sustain in the jungle and works very well with the battle cry passive to give you a ton of staying power.

armor 5 pots is currently the best way to go in the jungle and lets clear the jungle while still having enough health to gank multiple lanes. picking up boots 1 for the extra movement speed will make catching up a lot easier. wriggle's is a MANDATORY item for jungling with xin. Everything about the item is amazing, the whopping 425 bonus damage to minions makes farming the jungle a breeze and the ward every 3 minutes protects dragon/blue/red/whatever is important at the moment. Heart of gold gives extra gold production to make up for lost farm during ganks and roaming. the phage slow is deadly when chasing and makes it very hard for an enemy to escape without a flash. I get mercury treads or ninja depending on the enemy's team comp. Some will get berserker's greaves for the attack speed, but it is unnecessary when leveling battle cry first. Next get hexdrinker and warden's mail(warden's mail first if ad team comp and vice versa for hexdrinker). The bubble from hexdrinker will help either escape from an ap carry, or give you that last little shield in a team fight. Warden's mail gives you a good amount of armor and health regen while also giving you another slow effect to add onto the phage slow. Most games i get trinity force, because it is all around great item to get. It has all of the things xin wants, a slow, double damage, and attack speed. Frozen mallet is the other option to build off of the phage, but i only recommend this when they are hard focusing you or they are an extremely mobile team(sona, ahri, riven, ezreal, master yi). finishing randuin's omen makes you very tanky and gives you the sweet active slow that can turn a team fight around or help you chase enemies. maw of malmortius makes the bubble stronger and gives you a ton of attack damage with the % based bonus. after finishing the core build other directions can be taken but phantom dancer into bloodthirster seems to work the best. Phantom dancer makes you more moblie(awesome bonuses with tri force) gives you sick attack speed and more crit chance which is not irrelevant. Bloodthirster gives a huge amount of attack damage and life steal so you can stay in a team fight longer and kill squishies faster. warmog's and atma's impaler is another option but is less viable as the current build is tanky enough and gives you overall less ad and attack speed. It is however good if you are the main tank and need a large amount of health.

9/21/0 jungle masteries work very well and help out in the early game while still giving decent boosts later. They are pretty self explanatory so I won't go into too much detail on the masteries.

I max battle cry first because i do not build an attack speed early in the game and it is very important to have the life gain for sustain. Three talon strike is what xin zhao is known for. The op knock up and the large amount of damage is great, but it is not as good when you do not attack as fast as you do when maxing battle cry first. But, when invading make sure you get 3 talon strike first for the knock up. Audacious charge is the utility gap closer that doesn't need anymore points until level 14. It deals damage and gets you on top of the squishies, not much too it, but it is pretty cool when you throw down a ward at a creep camp and charge to the minions to help escape. Crescent sweep, just like any other ult, gets points at 6, 11, and 16. Knocks back all enemies that are not currently challenged by xin's passive and deals damage to them. This is a great way to focus an ad carry and get the entire enemy team off of you and your other damage dealers. WARNING make sure you challenge the squishy before you you your ult. Hitting a tank and then knocking back an ad carry will screw you and your team over, while giving the enemy ad carry an easy ace.

Smite is mandatory for jungling and gives you some utility to steal baron/dragon and gives you the extra gold with summoner's resolve so do not be afraid to use it as much as possible(except when you expect the enemy to attack baron/dragon). Flash is the best summoner spell and gives you an insane amount of mobility. Catching up to a runner, flashing over walls, escaping, it does everything and i suggest always taking it. Exhaust can be a good options if your support is bad or you feel you need the slow to kill an enemy. Ghost is decent and lasts longer than flash, but the overall utility from flash overrules ghost completely. Don't bother with any of the other spells, especially ignite because you want your lanes to get the kill and igniting an enemy prevents that from happening.

Pros:
-Tanky
=sick armor reduction
-op crowd control
-HEALS HEALS HEALS
-easy to play for the most part
-no skillshots!

Cons:
-Ult is the only escape mechanic
-needs assists or fed to do much in fights
-focused pretty hard
-needs good teamwork to capatilize on ult/knock up/etc.
-mediocre cooldowns

Invade! Xin is one of the best junglers to invade with, and with proper teamwork, first blood and blue steal will be easy. Make sure a point in 3 talon strike happens first if invading. When not invading start by getting a leash at wolves and blue continue to wraiths and golems and then get the red buff. You may need to help a lane in between any of these camps if they are off to an aggressive start and need help. Once red buff is acquired, you can start ganking lanes. Top usually needs the first gank because the bruisers have a large damage output early on and your top may need help. Order of ganks all depends on you watching the enemy health bars and how pushed their lane is. Tower diving is worthless at lvl 3 and you will just lose your buffs. Make sure you let your teammates know not to push the lane. If a lane is countered then they will need ganks more often than a lane that is well positioned. Use wriggle's lantern to avoid counter jungling, or if you are ahead use it to ward their blue/red to take their buffs and set them behind. If your mid lane uses mana you should definately consider giving them the second blue buff, especially if they are behind. In mid to late you are going to want your ap carry to always have blue, and your ad carry to have red so they can kite easily.

Xin Zhao is an awesome, aggressive jungler, that can gank easily and effieciently, and give your team first blood in almost every game you play with him! Happy Healing!