Welcome to my tanky support Taric build. I feel like taric doesn't really need ability power, and that turning him into a durable aura banner is much more useful.

The stats that Taric need are:
1) Mana regen - we get this from Greater seal of replenishment
2) Attack damage / Attack speed - Greater Mark of Attack Damage
3) Magic resist - Greater Glyph of Magic Resist

Since he really doesn't need anything else, i get Greater Quintessence of Gold for extra gold.
You can also get a Greater Quintessence of Ability Power for a bit stringer heals or Greater Quintessence of Health if you have problems surviving early enemy bursts.

If you feel like your hammer is just something you use to stand straight in the brush and don't plant on hitting anyone with it, you might get Greater Mark of Magic Resist instead of the attack damage one.

Classic utility masteries with a bit of magic resistance from defense instead of archaic knowledge from offense.

There are 3 main parts of my build:
1) I rush Mana Manipulator, allowing my ad carry to use her spells a bit more. It really shows especially with Caitlyn, Corki or Graves.
2) I follow up with gold generators, such as philosopher's stone and Heart of Gold. I don't get kage's lucky pick since i feel there are more useful items and i would lack inventory space if i got it.
3) Next, i get Soul Shroud instead of Aegis of the Legion. Now why the hell would you do that, man?! It's simple, Taric already has Shatter aura for armor, so getting an item that gives even more armor is not that strong. The point to consider here is: Do i want my carry to have more mana and cooldowns, or do i want it to have some magic resist and 8 more damage from aegis? I think the mana regen is more worth it, since i can rush it and get aegis later, should it be needed.

Now if you get Soul Shroud, you will be more efficient in longer teamfights, since you will not only provide the +10% CDR aura, but also +12mana/5 aura, which will help your caster big time. Plus you can heal more often.

I think Aegis of the Legion is a very good item, but having Soul Shroud just feels more useful and is my priority. You probably should get Aegis of the Legion when the enemy team has more champions dealing magic damage, like phoenix stance Udyr + Brand + Cho'Gath. Against a more physical damage oriented team get Soul Shroud.

Flash + Clairvoyance.
Flash is great for landing your Dazzle and stunning enemies that will otherwise be out of reach, or for just getting away.

Clairvoyance is very useful too, try using it to track the enemy jungler's progress whenever you can. Also keep an eye on other lanes, if your jungler is ganking top lane and the enemy champion is trying to hide in the brush, put your glowing eye there and ruin his futile and cowardly attempt.

As every dedicated support, you gotta buy wards and kill the enemy ones. Here's a few tips on doing that well:

- In late game, always have an Oracle's Elixir. You don't really need more items, it's imperative to maintain map-awareness with your wards and limit the enemy's by clearing as many of their wards as possible. To put it this way: You have your own personal warding war against the enemy support. Whoever manages to come on top and ward the map while denying wardage of the enemy will win a huge advantage for his team.

-But the enemy support has Oracle's Elixir! Warding is a waste of gold, i want my items! Now you are a support, and you are good even with few items. If the enemy has oracle, get one too! If the enemy kills your wards, do the same to him! If you see your wards dying in some spot, go replant them, the enemy is likely to think that area has been cleared of wards and will not look there again for some time. Always remember, vision is vital for catching enemies out of position or properly deciding where your team can fight. By warding you are helping your team a lot.

Using your heal ( Imbue)
You want to keep your ally at high health using imbue on them whenever they get hurt. The only exception might be a situation when your ally is low on health, you are low on mana, and a fight is imminent. It largely depends on the situation, but a stun with Dazzle is generally better than refreshing a little health with Imbue.

Using your passive ( Gemcraft)
In an all-out fight, try hitting the enemy champions, or if you cannot, at least hit enemy minions to refresh your cooldowns and make yourself more useful.

If the enemy minions are pushing and you are low on mana, hit some of the more healthy ones to regain some mana. Remember not to screw up you carry's last hits, so only hit the nearly full hp minions and only when you really need that mana or when the enemy minions are pushing (meaning there are more enemy minions and damaging a few won't push your lane).

Using your stun ( Dazzle)
If there is a stunner support against you, don't stun first unless your jungler is ganking. Most of the time the first stun flyes, the enemy carry jumps away, your carry jumps in, fires barely a shot and then the enemy stuns your carry. And because everyone is in place, he lands more shots than your carry did. In a stun vs stun situation you should watch out and only stun 2nd or when the enemy carry is close to you and your carry has some burst damage & getaway.

Using your armor aura ( Shatter)
Hit Shatter every time you engage after your stun. You lose some armor, but the armor aura you provide is unaffected and you will reduce the enemy armor, giving your carry harder punch. Be careful when farming minions with this while being alone in lane - then the missing armor can hurt.

Using your ultimate damage & AP aura ( Radiance)
Always hit radiance in big battles. If you can, get close to many enemies and hit Radiance and Shatter right after. Then get the HELL OUTTA THERE and try to stay alive, because you are a walking armor, damage and AP aura. If you cannot get to the enemy champions to pop your Radiance, just use it anywhere - as a support, it's damage will not be that great and your allies will benefit from the aura much more than from the initial damage.

Remember what you are - you are a walking set of auras. Armor, AD, AP, CDR, mana regen, if you got Aegis of the Legion then even more AD and resists. This makes you really annoying for the enemy team and turns you into a high-priority target. It is more important to stay alive and provide the bonuses to your team than to land a shatter, or hit enemies with your mighty hammer and regain some cooldowns to stun a bit sooner again.

This reason alone is why i am building Taric with tanky items and it also determines my "luxury" items. Ask your teammates which aura they need - and get it. Taric is a versatile champion and he can benefit from any aura in the game. Zeke's Harbinger, Will of the Ancients, Aegis of the Legion, Abyssal Mask.. you name it, you can use it. Now the fun part is that if you get 6 auras, you can basically just try to stay alive and land 1 good stun in a teamfight.. and you are being a huge benefit to your team by just running around.

Here is my tanky support Taric build, i plan to update it with a few good warding positions and maybe alternative builds against different team compositions. Let me know what you think, guys.