Here is my Shen build guide. It does me very and makes Shen a great team mate all time around.
For runes I use health marks, seals, and quintessences. This is just one of many rune builds out there. You would easily get armor seals or something like that.
Obviously hes a tank so 0-21-9 will work fine. If you wanted him to do a bit more damage, then you could go 9-21-0. Either one works.
The summoner spells I use are teleport and flash. Teleport is good for getting to the team fights because the tank always needs to be at the fights. You also could use it to cover a lane thats getting pushed and needs help. Flash is good for escaping, getting in position to use your taunt and just getting into position.
Different summoner spells:
Clairvoyance: Um...no your not a support
Exuast: Can be useful bot not recommended
Garrison: Dominion only...
Ignite: You don't want kills
Revive: If your bored
Teleport: Very good for getting to the team fights
Clarity: If you used this, you would lose
Flash: Yes this is very good
Ghost: This is also very good
Promote: Just don't do it
Smite: If your jungling then yes, it not no/
Cleanse: It could work but I've never tried it
Heal: It works but not as good as some of the others
Over all the best summoner spells to use with Shen are-
Pros / Cons
Pros: 1-Has good sustain in lane
Cons: 1-Not very fast movement speed even in late game
2-Shelid is small
3-Pretty easy to kill steal with his Vorpal Blade (q)
Creeping / Jungling
Shen is a viable jungler but I don't play him as a jungler. He is one of the slowest junglers in the game.
Early Game/Lanning Phase
If your lanning with a carry of some sort, you generally want to let them get the last hits. You can take a few but just not to many.
Late Game/Team Fights
You want to be at the team fight. Taunting all of them will help your team do a lot of damage to them with out your carrys taking damage. You want to make sure your carrys don't die but this might mean you dieing. Its all for a good cause. If you can figure out who on their team is being targeted, you would try to use vorpal blade on them. This might let your carries regain some health. You dieing is not the end of the world since your are the tank on your team.
Some tips are:
1-Use vorpal blade to let your lanning partner regain some health. Throw it on the cannon minion so they will get the most health back.
2-Taunting the whole enemy team will give you a lot of energy back so you could use your shield.
This is my first League of Legends guide so give me any feedback you might have!