iv played about 300 + games with shen now and this build works every time. Things to remember..your a late game champ...early your tough but you must play a cagy style. dont rush in...if you do..your not playing a tank. play a fighter. By mid game your making a name for yourself..people watch out for you and tend to run back.. Late to end game..your able to hold all 5 enemies off while your team decimates them. Welcome to my Shen!

Ok, before you decide to play shen..you must be willing to have little to no kills...but tons of assists...I have games where im dominating in kills, but thats not often. Shen is the rock the enemies should crash apon while your team kills them.
Champion Abilities

Ki Strike.
(Innate): Every 8 seconds, Shen's next attack deals 15 +5/level (+3.5% of his maximum health) bonus magic damage, and every time an enemy champion attacks Shen with a basic attack, the cooldown is reduced by 2 seconds.

Vorpal Blade.
(Active): Shen deals magic damage to target unit. That unit becomes life tapped for 5 seconds, healing any champions who attack it over 3 seconds.
*Cooldown: 3 seconds
*Range: 475
*Cost: 70 / 65 / 60 / 55 / 50 Energy
*Magic Damage: 50 / 95 / 140 / 185 / 230 (+0.65 per Ability Power)
*Heal: 10 / 20 / 30 / 40 / 50 health (+0.2 per Ability Power)

Feint.
(Active): Shen enters a defensive stance, shielding himself from some damage. Lasts up to 2.5 seconds.
*Cost: 45 Energy
*Cooldown: 9 / 8 / 7 / 6 / 5 seconds
*Shield Absorbtion: 50 / 100 / 150 / 200 / 250 (+0.6 per Ability Power)

Shadow Dash.
(Active): Shen rapidly dashes to a target location, Taunting enemies he collides with. Restores 50 Energy if you hit a champion.
*Cooldown: 10 seconds
*Cost: 120 / 115 / 110 / 105 / 100 Energy
*Taunt: 0.8 / 1.1 / 1.4 / 1.7 / 2 seconds

Stand United.
(Active): Places a shield on a target allied champion, which will absorb damage for 7.5 seconds. After channeling for 2.5 seconds, Shen teleports to the target's location.
*Cost: 50 Energy
*Range: Global
*Cooldown: 180 / 150 / 120 seconds
*Shield Absorbtion: 300 / 525 / 750 (+1 per Ability Power)

i always get Q first...the regen helps you stay in lane longer and if you only use it to harrass
it keeps them off you. wait to hit them with ki strike till later...makes your opponent underestimate your power. this will often get you first kill.
Then focus on feint and vorpal until lvl 5. then add dash. this is because your not going to have enough armor and health to use dash efectivly.
so Q,W,E,R
always add to R when u can. this makes shen the beast on the feild..be aware of the board. watch your team to ult in and get kills / saves.

i always get ghost and teleport, these combined with stand united lets you control the entire field of battle. your enemies will hate you, your team will love you!
If your in a 3 vs. 3 take ignite or heal. i like heal, I know everyone says öh heal noob"but seriously after getting beat down in team fights cause they have 3 heals...it just works.

Dont jungle..your not made for it! That being said, dropping off grid to get a little extra gold never hurts, but your better suited to stay in lane, you will get more exp and gold that way. and with shen you can effectively lane alone letting someone else like WarWick jungle and get beefy.
If you play this way and watch your team to ult in and save / kill you should be known as one of the best Shens out there!

First off buy dorans shield and an hp pot. this gives you great surviveablity early game. then always get first and boots next.The hp you get means everything with shen, ki strike feeds from your hp and it will immidatly make you a force on the feild. merury's treads merc's for ap heavy teams, or ninja tabi for dmg heavy teams..boots are yours to choose. next get warmongs armor, the hp and regen are your bread and butter. Then get thornmail or force depending on what you need more, magic defence or armor. then get atmas, always a nice bet with a hp heavy tank like shen. as for end game items...you chose based on the game..i like to add a warmongs because of the hp bonus and dmg output it adds to ki strike.
dont stack sunfires as of the last patch they nerfed it so the dmg dosent stack any longer.
its a waste and i always laugh at those who still try it.
Now I'v seen those who go for randuin's omen in 3 vs 3. it may help since its cheaper to put together..but i cant stress enough....take the giants belt always!!! with this simple trick you will notice total domination....make them all fear the ninja!