This build allows you to do a lot of quick damage but also gives you the ability to last along time in a team fight even if you get focused.

I like to build xin as a tanky DPS. For runes i get armor reds for a little more survivability. I get mana regen yellows since xin's abilities are very powerful and can be costly if your regen is low. this allows you to spam and not worry as much. I get magic resist blues to allow you to just tare apart casters. The flat health quints are very useful in early game giving you a chance to get some early kills that make you unstoppable.

Xin is a DPS so go with 21 , 9 , 0 on your masteries getting every damage increase in offense and some resists, dodge, and health regen in defense.

Three Talon Strike is Xin's bread and butter. The bonus damage followed but the knock up allows him to get some ridiculous kills. I always max this first and then get his other two short cooldown abilities.

Xin really doesn't need any specific summoner spells. I usually get ignite for help with early kills and ghost for quick getaways. Other suitable summoner spells could be exhaust or flash but it is really up to you.

Starting with a dorans blade and a health pot will allow you to farm and get some fast early levels. The life steal, damage, and health from it make a great starting item. My Xin build is based of Atk. speed, movement speed, life steal, and toughness. You wont do quite as much flat atk. damage as other xin's you have seen but you will be nearly impossible to kill. Phantom dancer is a great item for both atk speed and movement speed and i get it on almost all of my DPS champions. I get Mercury treads for the reduced stuns, fears, taunts, etc. The Bloodthirster gives good life steal and damage. Frozen mallets slow is essential to a lot of kills because once attacked once they are not getting away. Finally a Banshees Vail and a Warmongs armor increase his survivability.

Early game:
Try to get as many last hits as possible since this build can be costly. Use the combo of audacious charge followed by a three talon strike as a poke to keep enemies back. once low enough use this same combo to finish them off for some early kills.

Mid game:
Once you hit about level 8 and u have your dorans blade, phage, zeal, and mercury treads you can easily gain some quick levels by clearing out your jungle. Don't forget to gank you can get a few kills this way. always initiate with audacious charge and then hit your three talon strike so you can get all three attacks of while they are slowed.

Late game:
hopefully by this point you are very feed so be aggressive. don't be afraid to go in for 2 v 1's. with this full build you will be very powerful and difficult to kill. try to use your ult. early in a fight so it will deal the most damage allowing you to kill your opponents faster.

Give this build a try. i've found it to be very effective in both 3 v 3 and 5 v 5 games so feel free to use it where you please. it works well in ranked games as well so good luck and have fun.