Exhaust is vital in a standard bot lane, it is so very important whenever fighting each other heads up 2v2, and Taric strives for these 2v2 fight situations. 

 Flash is a staple for almost all champions barring a few exceptions. Taric works well because he can catch people with flash-dazzle or he can be super aggressive, whacking people with his hammer then flashing out at the last moment. 

 Heal + Exhaust combo is for the real manly gem lords. If you are looking to play MEGA aggressive, or just trying to bully them out of lane 100% - say you are going against something like a Vayne or Kog'Maw, heal + exhaust is the best way to win a lane. This combination is not as good as flash later, and may leave you susceptible to ganks, but will crush your lane in 2v2 fights. 

These runes are based around early game aggression. You get the movement speed quints not only so you can position and use your stun at more precise timings, but also so you can abuse your auto attack when fighting in lane. To keep with the early aggression, we have armor marks and partially armor seals. We want to have some gold income, so kept a few gold seals on, but at the core Taric's purpose is to be a tanky beast - so we keep the armor strong with armor marks and several armor seals, this combo'd with his shatter armor, and an early emblem of valor should keep him well above the 100 armor mark early, a nightmare for the opposing AD carry. Lastly we have flat mana regen blues, this again is for early game aggression. Taric's mana pool is VERY low at low levels, so these flat mana regen (opposed to scaling) will help him play VERY aggressive in the 1-5 levels, stunning and forcing trades as much as possible! 

These masteries are built around a tanky support focusing around early trading. We get improved exhaust so we can burst people with the -armor/mr. Then get health regen and armor in defense - stacking these stats with our Shatter aura, as well as our Emblem of Valor rush will give us great trading potential. For utility we get the standardish support masteries, mana regen being more important for early trading than MS out of combat. 

Starting Build:

Anti-AoE

 This is a new item that upgrades from Aegis. This is a late game specialization item, not something you should rush. The upgrade from aegis->bulwark is primarily focused on a stronger Magic Resist aura, this is a good choice vs people like Karthus, Vlad, Galio, etc. - it's a good support answer to AoE strats like we have been seeing. 

 Locket is roughly the same as before, but it has gotten better a bit by adding kindlegem instead of HoG for upgrade path. This again is a great item vs AoE because it gives nice shield to all team members as essentially a counter-AoE design. Great item vs the common AoE ult teamfight stacked teams of these days. 

Protecting the Carry

 Zeke's is a great item for protecting the carry, the lifesteal which has been generally nerfed is still strong in this item, and it has been tuned up a bit so now it gives AD and Lifesteal rather than attack speed. Overall its a great choice if your AD carry is strong or if your team is stacked with brusiers. 

 Crucible is a new item which is essentially a QSS you can cast on someone + heal. This is great support item, although it can give excessive mana regen to someone like Taric, the active is too good for protecting the carry.

Diving into the teamfight

If you find yourself as the only tanky person on your team, or that you are always being focused, this can be a good item to pickup for you. It has changed since the last patch and it is now more even (slowing every time you are attacked, rather than chance), and the active is a bit better. This is now an acceptable option, but one I would only get rarely - it is better to play in the back of teamfights than diving the opposing team. 

Misc Items

 This item gives you the active of what old Promote did. This can be useful if you are going for a pushing strat or something. I would only pick it up if I had the intention to before the game started - not quite something that I would do in every game. Can be fun to play around with though, it makes the minions really fast !