You probably think I'm trolling at this point (or you know exactly what I'm about to say, and you're here to better your skills), but bear with me, I shall explain. Taric's passive, Gemcraft, now does this:

"After casting a spell, Taric's next basic attack deals bonus magic damage based on his Armor and reduces his cooldowns."

To be more specific, after casting a spell, Taric's nect basic attack deals 30% of his total armor as magic damage, and reduces all cooldowns by roughly 2 seconds. Think about it! You can build flat armor and still pose a significant threat to the enemy team. Successfully getting your combo off on an enemy is massive amounts of damage, while still being surprisingly tanky.

In the early game you must play passively. Farm as best you can, don't take too much harass (otherwise you'll spend to much mana healing yourself), don't push too far, since your only real escape is flash or a well timed Dazzle. Taric is susceptible to level 2 or level 3 ganks, with that in mind play cautiously. Remember to pick up wards.

Now that you know what not to do, here's what you can do: If the positioning is right, casting Dazzle before quickly running up to smack your foe once is a decent tactic. Taric can usually win trades if your spells are timed well. I would suggest using E, Q, W combo, as to not pop your armor buff passive until your foe will not be striking you again, for maximum defense. Using Imbue while trading is a sneaky and satisfying strategy; for example:

"Just as your enemy thinks they won the trade, you heal yourself and smack them in the face!"

Be mindful that a lot of top laners are burst-based, never cast Shatter until you are retreating, otherwise you may lose trades. Once you reach level 6 things will change, usually for the better.

After hitting 6, you should have some sort of item/s building into an Iceborn Gauntlet, meaning you can go in for a kill. I would suggest using E, R, Q, E, W, and try to keep the chase going to fully utilize Radiance. Do not go in unless the river is warded. If the enemy Jungler shows up, back away and save your own life. It's better neither of you die than a kill and assist for the enemy team. If the circumstances are favorable to get a kill, try for it. Don't foget to ask your Jungler to help you out now and again.

Once one of the top towers is down (hopefully not yours) you can start roaming! This is Taric's most awkward phase, since he is between items (you may or may not have IbG yet), and it's difficult to do much by yourself. Find a buddy (Preferably Ezreal <3), and start looking for targets. Overextended, alone, or just plain out of position targets make the best prey for you right now. Be careful of baits, as Taric is still weak.

When getting into skirmishes, try and bait the enemy as best you can, using Q, E combo for maximum frustration of the enemy team. Honestly, Taric still can successfully 1v1 most of the squishier AD champs, but unless you have vision on the rest of your foes, don't try anything too risky. Fortunately this is the phase that lasts the shortest, and once you have 3 full items, you're ready to start being fabulous.

The late game is where Taric truly shines. Now that you have most of your core items you can start initiating teamfights. When going into a fight remember to always cast Radiance a the fight begins (it's basically a mini Baron buff), giving AD and AP to nearby allies. I would suggest using E, R, Q, E, W, Q, E during temafights. If you're getting your passive off successfully then your cooldowns will be resetting faster than you may think. It's not too difficult to focus the squishies and get or assist kills. It really doesn't matter whether you get the kill or not, as long as you're making some money.

Taric turns into a huge tank towards the end of the game, remember that! Make risky moves if it benefits your team, you can usually escape from one or two enemies because you will be so tanky. Surprisingly, Taric is also an excellent lane-clearer. Split pushing is not a terrible idea, though you will benefit your team more in teamfights, with you auras, heals, and stun. Never be afraid to solo the ADC! As long as you know the enemy isn't on their way, you should have no problem taking the lone ADC out. Watch out for AP bursts, and too much hard CC, and you will do fine.

Pros

-Incredible passive
-Can easily 1v1 ADC's late game
-Late game scaling is very good
-Provides wonderful utility in teamfights

Cons

-Not so good early game
-Only works well against AD heavy teams (AP shuts you down)
-Mana problems in lane
-Can't do much unless well farmed

This guide is not finished, I hope I can get it done by EDIT: March 2nd, but I am rather weighed down with school currently. Stay tuned and I'll finish it as soon as I get the chance.

What to expect:

I will explain the following in depth:
-Masteries
-Runes
-Summoner Spells
-Skill Sequence
-Item Builds
-Counterpicks
-Conclusion