I am a toplane main, in a non-competitive team (Go KSGG!) and I love to play a lot of Shen, Sion, Darius, Xin Zhao and am starting to learn Rumble. I also play a bit of Talon and Susan if we go into a ranked 5v5. I have played Shen ever since I started this game (around the middle of season 4), and have to say, he's one of the more diverse toplaners (Or junglers if you're into that sort of stuff :^)), with lots of sustain (if played properly) and a hell of a shield. Now, I know I seem like a noob to a lot of you "Diamonds", but you have to realize, I'm a toplane main, and am getting little to no deaths at the end of games, against people higher leveled than me. In one very long match, I died 9 times, the most I have died in a match ever, and due to my general tankyness, we won that game whilst I pulled a "Singed" (running around aimlessly) and distracted them.

Hopefully, you're going top and you've taken your Runes, Masteries and Items.
You need to focus on freezing your lane at your turret, as Shen is a good "Under turret farmer", because you have that good passive for farming, (Ki strike, your passive, also scales with health, the thing you'll be buying!). Once you have gotten first blood, you will begin to gank other lanes and secure kills. When your other laners are sufficiently fed, you will begin to either split push, or group mid and force a fight into a Baron. Either of these options will result in victory. If you haven't gotten first blood, you should play as much defence as you can, as there will be lots of ganks coming your way.

Pros:
Your team gets an incredible tank, with sustain for the Bae, an unbreakable shield (after 2 seconds) a "taunt" and a massive shield for the most fed person on your team.
A strong gank game, and a strong lane phase.
If played correctly, can win all match-ups.
Cons:
Low damage, only one "cc" ability, people will just zone the Shen early and gank him repeatedly.
Campable, as you can't even fend off a feeding Warwick.

Shen is an easy champ to farm with, once at 2000+ hp, as Ki Strike gets you amazing damage on your basic attacks.
An average 20 min cs game for Shen is around 80-120
A game that goes up to an hour requires around 200-250

I'm going to congratulate you on picking up one of my favourite tanks, and I hope you do well with him, you really have to do good, you can't do much else!

-Logan (KSGG Psychosis EUW)