The purpose of this guide is to maximize the global presence. This is accomplished in several ways:
Maximize minion push
Increase your minion help while pushing (Health Regen, Super Minion)
Reduce Cooldown of Global Ult
Minor ability power increase will help with will help with shield.
I have seen a lot of different builds for Shen and have learned some different tips and tricks, however, I haven't had much luck with any of them as a whole. I imagine that different play styles may be a little more advanced than mine which may explain. These item builds are simply the ones that started working for me as a beginner tank, when others didn't.
Here are some items that I do not generally see in any Shen builds, however, I have found great luck with them:
This is one of the first major items that I get, usually after Doran's Shield, Heart of Gold, and Mercury Treads. I find that the extra health helps to be a little more durable, the extra damage helps with minions and the occasional early game 1v1, and the slow down helps in conjunction with Shadow Dash to keep people in range during ganks.
It's cheap and if you are doing your job, you should be getting tons of assists (and the occasional kill), which means uber-health. Once you get to 20 stacks, the 15% damage mitigation is sweet.
The 950 + 450 Health and 30 + 15 health per 5 is awesome.
This is usually the most optional of the items and I find that I use it in cases where there are faster/lighter enemies or where our team is heavier with less DPS. The extra speed, slowdown, health, and a little extra damage output seems very helpful for closing the deal in late game team fights.
NOTE: The obvious challenge is the lack of armor and magic resistance with these items. If the team is heavy AP or AD, I usually substitute out the Trinity Force for appropriate armor or magic resist gear.