This is my Xin Zhao build. This builds damage output is ridiculous. if finished one can easily solo baron nashor. it is a high attack speed, and high crit dps build.

For runes i do arpen marks, attack speed seals, health glyphs and apren quints. arpen is essential for any melee carry like xin, it adds very high damage to every target, and allows for some easy kills early game. attack speed seals because out of all the champions out there xin zhao benefits far more than most from attack speed. because his 3 talon strike relies on attack speed for how quick it actually disables them, his passive which gives health back on 4th hit, and his battle cry which when activated cools down every ability buy itself by 1 second for every standard attack made. the health glyphs are simply there because they save my behind more than often enough.

alternately i would recommend cooldown glyphs.

this masteries build is pretty standard for physical damage, its simply get to the end of attack and then make myself harder to kill.

for my item build my reason is pretty simple. it has a very high damage output.

berserker's greaves - because everyone needs some move speed, and xin needs attack speed to function.

2 phantom dancers - because a fast moving xin is a happy xin, and because they have awesome attack speed and great crit chance.

infinity edge - because of the strait up ad boost, as well as the crit chance, and crit damage increase. this item synergizes very well with the phantom dancers, once you have both the phatoms and the infinity nearly every hit will be a crit. rarely will you see a regular hit. and since we can assume the next hit will crit, the 250% crit damage is extremely beneficial.

2 blood thirsters - i build these because xin needs some good damage as well. when at full stacks both of the blood thirsters will be giving 100 damage each, as well as 25 percent life steal each, and when you're putting out 1300 crits every hit on minions it pays to have 50% lifesteal.

i find xin to be relatively easy to play, you dont have to run back as often from your passive and none of xin's abilities use much mana. i find the best way to enter combat with xin is with surprise. i would recommend activating three talon strike before you charge in, and after you charge use your ultimate if you have it, and then hit battle cry as soon as possible. if they dont die in under 3 seconds which is usually what happens, you will find you have another three talon and audacious charge to use.

you need to keep in mind how squishy xin is, he has low health and barely average armor and resist. getting disabled in a group of enemies, or by a single high damage enemy you can easily die.