For starters, with this build I ussualy goes solo, it works going with someone else but since you want the gold from the kills, I suggest going solo.
Most of the time when I play solo I get a kill at lvl 3, even 1vs2.
Reason: At lvl 3 you can Stun someone, deal dmg with Shatter and then run back healing yourself. After doing this twice or thrice I ussualy ghost in and go for the kill.
And as with all AP taric builds, late game your heal is freaking amazing.

Mid game and late game you are a bit tanky aswell, with about 115MR and 120armor, you won't be a tank but you will be a bit tanky.

+ Great dmg early and mid game
+ Great heals late game
+ Nice farm
+ Can go 1vs1 with anyone
- A bit expensive build, so you'll need kills
- Not that great dmg late game, but still enought to finish off a squishy in 2 bursts
- Long CD's since you won't be getting any CD reduction

Well I choose the runes I did because you got 28AP at lvl 1 with Dorans ring, which is quite high. Your AP goes up enough to make your heal heal alot even at rank 1 early game.

Magic pen is obvious, your stun and shatter deals more dmg.

You could also replace the +4.95AP quintessence with +AP/level quentessence.

Well, quite regular 9/0/21 build for Taric, improved ghost and clarity instead of flash or cv.
The only thing I would change here is that I could remove my "Greed" and "Expanded Mind" to get longer buff durations but that depends if you think you are gonna have blue buff alot.

I would recommend taking blue buff everytime you can, since your ultimate drains ALOT of mana in teamfights, together with Chalice of Harmony your mana goes up really fast.

Well the only thing I can say is that with this order you are gonna do alot of dmg. At level 2 you can get heal instead of stun if you are getting low on health, but then you pick stun on lvl 3.

Items.
Well, as stated in the pros/cons you don't have any CD reduction items here, so what you could do is change your Rylais into Morello's Evil Tome, I don't think it's needed but you can do as you wish. You could also change the rylais into a Rod of Ages.

The reason why I buy these items is because:
Dorans Ring#1: Gives you health, abit of AP and some mana regen.
Dorans Ring#2: Makes you really tanky early game with lots of health, nice heals, good mana regen.
Mercury's Treads: Well you can go with these or the Sorcerer's Boots. But I like these because they make you a bit more tanky.
Chalice of Harmony: Around the time you get this you should have noticed you have some mana problems, sure the blue buff is enought but you won't have it all the time.
Sheen: Gives you mana, AP and a really good hit after a spell. Taric has incredibly high AD with no items, add his ultimate and you can get this to hit for alot of dmg, also builds the Lich Bane later.
Will of the Ancients: This and your ultimate makes you win alot of teamfights, your AP carries will heal alot, and you can focus your heals on the AD carry or the tank.
Lich Bane: Gives you some more AP, MR and a new nice dmg output. By the time you get this you should deal more dmg with this hit than with the sheen.
Rabadons Deathcap: Lots and lots of AP.
Rylais Crystal Scepter: HP, AP, slows the enemy... Can be exchanged for Rod of Ages or Morellos Evil Tome.

Farming as Taric if you play according to this guide is really simple, just hit the minions once or twice each, shatter and they will die, soon enought your shatter will kill all the minions by itself.

Also with your passive, which gives you mana back each time you hit something, hitting minions for mana is an excellent way not to go out of mana.

Team work is really important for Taric, in a teamfight you shouldn't stun the one with the lowest healt to get a kill, stun the one who would have given their team the advantage if not stunned. And you should have full mana before each teamfight, fix it with blue buff or whatever, cus you are gonna go out of mana with Taric's ulti. In a teamfight Taric's ulti should be on the whole time.

What I ussualy do in a team fight is:
Stun
Ulti on
Shatter
Stun
Shatter
-no mana- (ulti goes off)
clarity
stun
ulti on
shatter
-teamfight ends -