First guide. Thanks for reading.

Taric was my favorite champion until the nerf. While looking for ways to make him viable again, I noticed that Taric Bot in AI games gets a Nashor's Tooth. I tested it and liked the results.

This guide assumes that Taric is going bottom lane with someone who is ranged. It also assumes that you won't take blue buff ever.

Pros
-Can spam abilities mid-game
-Cooldown on Imbue feels like the gold-old days
-Surprisingly bursty
-Off-tank finish

Cons
-You will be focused
-Slow
-Poor farmer
-Difficult to clear minion waves without leveling Shatter early

I find Taric very inflexible with Runes and Masteries.

MARKS - Magic penetration. Not negotiable.

SEALS - Because our only MP/5 item will be Nashor's Tooth, you will need MP/5/lvl seals. If you don't like Meki Pendant as a starting item, switch these for flat MP/5.

GLYPHS - Flat CDR is very important for Taric's heal, which at first level feels like it has the same cooldown as revive. With masteries and flat CDR runes we will have 15% CDR at level 1.

Quints - With MP5/lvl Quints we can spam our abilities late game without worrying about mana. Again, the only mana regeneration we are getting from items is 10MP/5. These take the edge off, but can be switched out. Good alternatives are flat AP and flat HP.

Masteries - Standard 9/0/21.

COOLDOWN REDUCTION - With our runes and masteries the CDR on Nashor's will bring us to 40%. Congratulations, we are done worrying about our high cooldowns.

Mana Regeneration - At level 9, with Nashor's Tooth, Runes, Masteries, and natural regen, we will be regenerating 5 mana per second. Along with our passive, and our ability to heal, we can stay on the battlefield for as long as we want.

Ability Power - All of Taric's abilities scale off of ability power. Moderate AP is necessary on Taric.

Attack Speed? - This helps in a few ways. It procs our passive 55% faster, it gives us added damage, it synergizes with Radiance which increases Attack Damage, and most importantly - it significantly reduces the cooldown on Imbue.

Nashor's Tooth is expensive, yes, but it contains a full package of everything that Taric needs for mid-game.

When to delay Nashor's Tooth
If an enemy is fed early, or if you don't feel confident with your teammates going into the team-fight stage of the game, you should delay Nashor's Tooth and buy a gold/5 item. Mid-game Taric's burst is nice and he's moderately beefy, but he is not enough to carry with any item. So if your tank is getting ROFLstomped, and your team is forced to play very conservatively, build a Heart of Gold after Fiending Codex and Merc Treads, and wait it out.

Mercury Treads and Nashor's Tooth are our core items. This will put us at full CDR, and give us the mana regen to stay in the fight; roam; or push. We will be the 'sustainiest' champion in the game.

After Nashor's Tooth and Merc Treads are built, Taric can focus exclusively on survivability and AP, and prioritize based on the situation.

Viable items include:

Aegis of Legion - I won't go as far to say this item is necessary on Taric, but it's usually the best choice for your third item.
Rylai's Scepter - This is one of those items I always want to rush, but never can. It's a great item on Taric, with its slow effect, its AP, and most importantly its Hit Points. The problem is that you will be focused hard in team fights before you can finish it, and will likely need Magic Resist, before you can afford an AP boost.
Abyssal Scepter - AP, Magic Resist, and a buff? The only reason you shouldn't buy this item is if one of your mages is buying it.
Randuin's Omen - My favorite tank item. It's not as viable on Taric as other items, but if you build a Heart of Gold, or if the Active will really help your team, you'll want to complete this item late game.
Banshee's Veil - Magic Resist, Mana, some HP, and one of the best Passives in the game. In some games you won't need Banshee's Veil, in most you will. If you know for sure that you will build a Banshee's Veil, build Catalyst the Protector before Stinger.
Thornmail - You will be focused. This is usually a better option for you than your team's tank, if Attack Damage is a problem.
Sunfire Cape - The best 'effective hit points' vs. Attack Damage item in the game. Often you won't need Sunfire Cape, but if you know you'll need it, try to rush it after Nashor's Tooth, because it will REALLY help farming.
Guardian Angel - Situational, but usually built in 60 minute games.
Stark's Fervor - Situational, but sometimes your team composition requires this item, and you are the one who should build it if your carry asks you.
Zhonya's Hourglass - I have never tested this item because by the time I could afford it (and if the game lasts this long, which it usually doesn't) I want to build something else. On paper, though, it is an amazing late game item for Taric.
Rod of Ages - This item is also untested. I've included it, because it is a great item on paper. The problem is, you won't farm enough to build it early, and it's one of those items that you should get early.

Don't forget to ward! You are the person who should buy them.

Unlike runes and masteries, I find leveling skills on Taric to be extremely flexible.

I like leveling Dazzle first, because it hits like a truck, and it makes enemies think twice about getting close to you, which makes farming and gaining mana through melee attacks easier.

By all means, if you need early armor, or you need to clear minion waves faster - level Shatter; if you are getting harassed hard by lvl 3 Galio, put some points into Imbue.

Flash - Necessary for initiations and to achieve maximum Dazzle damage.

CV - If you chose Taric, you are most likely the teammate who should be taking this invaluable spell. It has increased importance on Taric, because ideally, Taric should be pushing minion waves with his auto-attack to gain mana back at early levels. This will leave you vulnerable to ganks, and Clairvoyance will help you keep track of their jungler/roamer.

If you don't want to take Clairvoyance, replace this spell with Clarity, Ghost, Fortify, Exhaust or Ignite, depending on what you need on your team and in bottom lane.

I wanted to post this idea more than I wanted to build the best Taric guide on mobafire. Please test the build yourselves. If I get positive feedback, I will turn this into a full Taric guide and spend time making it look nice.

Thanks for reading. Ruby for vigor. Opal for harmony. Nashor's for win.