This is my first guide. I'm a casual player and this build does me well for top laning. Usually I have the first two towers down between the 17-20 mark. Since Xin has no real escape your only choice is to stand and fight. One could build defensive items but I believe a good offense is the best defense. So I focus items to increase attack speed and life steal. These items along with the passive heal you gain from W help dismember the enemies and survive. Its pretty common for me to go ~15/~5/~8 a game. Also I'm a fan of keeping things short and sweet so let's have at it.

I start off with the flask and save the rest of my gold. If I am holding my own in the top lane I start building a Tiamat. If I'm having difficulty then I build a Sunfire Cape. Second item I build is always boots. From there I start building the early-mid game items. The idea behind my item selection is:
1. Tiamat helps you farm gold from minions fast. Sooner you have it the sooner your gold increases. Sunfire Cape if I'm having trouble, helps farm gold and gives protection.
2. Bilgewater cutlas life steal and attack damage with a weapon activation that can slow the enemy.
3. The Stinger's attack speed and CD reduction.
4. Zeal for the extra movement speed and attack speed.

The goal of my item selections is with the passive heal from W plus the lifesteal plus attack speed should help keep you up and put the enemy down. The only down side is if you are constantly stunned. Stunned Xin can't attack and rebuild lost health. With these items you can put a hurting on towers fast so those coward enemies can't hide beneath them.

With the Flask, you can put off your W and get your E sooner. Generally I max out Q first. Then once both W and E are at level 2, I focus on maxing W, and finally E. I always max the ult when available. The Q masks your total possible damage. People think I am not all that powerful but once the Q pops they feel the pain.

In short, R>Q>W>E.

I like the bonus armor from hardiness. If you need magic resist go for resistance then. I hate cooldowns so I chose to max out Sorcery. Attack speed is great for Xin due to passive health gain. Summoner's wrath is my choice. I prefer ghost over flash due to 10 seconds of haulin booty. Ignite is obvious for obvious reasons. Bonus 5 attack damage is just an extra perk.

Armor pen is a hidden stat. You can't see it on the screen. They may only see 60 AD at the start but the Armor pen is hidden. They may think you are weak and get a nice surprise. Also you get maximum benefit from the start. I like both health and armor so I do about 50-50. I do like having extra AD so I go with that for the quints.