This is an aura*****/support tank Taric build.
You want to focus on raising Radiance, Shatter, Imbue, Dazzle in that order. I start by taking 1 rank of Shatter, then Imbue, then Dazzle, then stick to leveling the skills using the method above. You want to blow Shatter to farm minions and to lower armor in team fights. Always have radiance on during a team fight. Blow Clarity to sustain it if the fight is still going on. Try to blow your stun on a carry to minimize incoming damage. Clairvoyance is a must for map awareness. You won't be as strong as a full tank but you should be able to take some damage. You're a support tank though. Taric works best with a melee heavy team because of his ultimate. You want champions like Yi, Ashe, Tryndamere, Tristana, Sion, Twitch. One of the best champions to have on your team is Sivir. Taric's ult synergizes very well with Sivir. Be careful of heavy magic dealers as Taric doesn't have much magic resist. You want to be with your team as much as possible due to Aegis and Radiance. Have your team help you get the golem rune buff for awesome mana regen and cooldown reduction.
Opals for Harmony!
Rubies for Vigor!