Link to my Mundo build: http://www.mobafire.com/league-of-legends/build/dr-mundo-the-killer-tank-tank-tank-killer-843
At the beginning of the game i usually take bottom, no matter who else is there, this will allow you to to kill the dragon at about level 8, good for extra gold. The Ignite is to always get the kill, even if it means Kill Stealing.I have found it very successful, almost 1\4 of my kills.
So you will start out with a health potion and Doran's Shield. You may not even need the Health potion for the fact that you are a tank. You Should spam Vorpal Blades making sure to keep the two enemies in your lane at low health. With this in mind, it doesn't matter who end up being you lane partner, you may even end up soloing, which is better for Shen because of the mass health he gathers from leveling and his ability to keep enimies at bay. Now if your going for a defensive Shen then you will want to get a Vorpal Blade then put all the points you can into Feint. As this is an offensive build i like to go for the Vorpal Blade and the Shadow Dash, Going for Feint at the last possible points.
Keeping this in mind as this is a offensive tank build,upgrade Shadow Dash and Vorpal Blade as much as possible, upgrading your ult whenever possible.
It's very possible to get first blood, which is why i have Ignite, as it is useful later as well. The reasons I did not pick something like Ghost or Rally etc. is that I did not find a need for it. Shen is reasonably fast as it is and he can also transport using ult. With Ninja Tabi Boots he will be very fast.
As soon as you can, buy Warmog's Armour simply cause of the 770 health you receive along with the other bonuses.
Now your probably wondering why I bought Nashors Tooth, it's simple, 30 Attack Speed, 55 Ability Power, 12 Mana Regen. UNIQUE Passive: Reduces ability cooldowns by 25%, whats not to love. This cooldown will make your ult fast which will let you move more freely about the map, and to dare I say it, get a Kill Steal or two. Your going to want as much CD as possible, its allows you to get round the map very efficiently, its about an 81 second cooldown by the time your lvl 18, This allows you to, say, teleport top kill both people there, push a tower and then teleport bottom when other team tries to gank.
Because of the rare deaths that Shen might have in a huge team fight,i have bought the Gaurdian Angel. This way if by some miracle you are killed you can just resurect(spi) with it. I find it very difficult to die while using shen and almost impossible to not get at least 10 kills. by following the guide i have built you should be fine. I find it HARD to die with Shen, if you play him smart\right you should never die. I say that I find it hard to die while playing as Shen, and while that is true, I pick up Guardian Angel just in case, as a precaution. The way I stay alive, is don't always think for the long range teleport, at low health I killed a full health Ryze and Stealthed Evelyn. I did this by Teleporting to my teammate right next to me and pushed super hard for the kill.
Any comments or critics feel free to post.
And yes this is the same one as for, but i meant to save and publish later but i misclicked and as a result have gotten negative votes, so this is in hope that people read my description next time.