[E01]STRATEGY: Early Game
Pray that the other team has a jungler! Before the minions spawn, you have a lot of things to do. Place a ward at your Elder Golem brush, so that you can see the Elder Golem. Place the second ward around the enemy Lizard Elder camp. Get as many team mates as you possibly can to go to the opponents Golem Elder camp, and kill their jungler, if the opponents do not show up, kill the Golem Elder instead. With a few champions wailing on the poor monster, it won't take long, and everyone should be in their lanes pretty quickly. use Health Potions to heal up if needed.
Before returning to your lane, follow two of your allies into theirs, or call a gank on middle. Usually 3v2 or 2v1 will be successful this early on thanks to a combination of Exhaust and Dazzle, as well as your allies and yours early game damage output. At worst, you will have severely weakened opponents that can be finished off later or that has to go back. Having done this in one lane, go to the other, and either scare or full on gank again.
This early game shenanigans will give your team an easy lead, while not hampering you in any way. After ganking twice, go back to your lane, where your partner should be around level 3 or 5. Play a bit more defensive here, as you need to get to level 3 or 5 yourself. If your partner feels they can score a kill at level six, assist them in doing so, but other than that play "passively".
There is some interesting stuff you can do even at this stage, once you've hit level 2, and can sustain harassment from the opponents. Usually it's beneficial to try a gank even as you enter your lane, if your health and mana allow it, to force the opponents to be more cautious. From here, your job will be to sit in the brush and zone the opponents as much as you can, while your partner free farms. To zone an opponents simply run out of the brush, cast dazzle, and Shatter > Hit them. Then run back into the brush and Imbue your partner and yourself. End effect should be both of you seemingly unaffected and with opponents missing 200-400 health with each "poke".
The key here is to let your lane mate free farm. You don't need the money, as you'll be able to afford everything you need when you need it through assists and simple gold flow. Remember to respond to any gank requests, as well as call lane switches if you see one lane significantly dominated. BE PREDICTIVE rather than responsive in your behavior. If you are on bottom and you see your top is tower hugging, investigate by looking at their situation, if you see they are very low on hit points, and are about to die, instantly call a lane switch. Remember to harass middle as you run through it. Keep your opponents on their feet.
[E02]STRATEGY: Middle Game
You should have acquired Chalice of Harmony and in the very least Boots of Speed. Stock up on Sight Wards and place them in opponents jungle areas. You are moving the ganks away from lanes, and making every area of the map dangerous for your opponents. If you find an opponent overextend in the jungle, instantly go in for the kill. This will force your opponents to just tower hug, or travel in big packs. Both are beneficial, because when they travel in big packs, you can easily avoid them (you should have the entire map warded), and if one does break off, you can once again kill them. If they tower hug, you will slow push in their towers.
The key is to ALWAYS have a 3 stack of Sight Wards ready to go anywhere they need to be. You should have most of the map revealed.
You'll also have to make a decision between Stark's Fervor and Aegis of the Legion, basically treat Stark's as a roll harder item, while Aegis should be purchased if your squishes are getting heavily focus fired in fights.
You are also an amazing tank at this point, so feel free to initiate under towers, and so on, between your improving Imbue and radiance, you should have no problem walking out of most skirmishes alive, with hopefully a bunch of opponents dead.
[E03]STRATEGY: Late Game
Your tanking capabilities are significantly diminished at this point, you should fully embrace your tanky semi-dps support role. Keep providing your team with wards, and make sure to be there for every team fight to throw a few clutch heals on your squishies, as well as to provide a significant physical damage boost to your entire team. Save your stun for the likes of Galio and Katarina, as well as any carries that might dish out large amounts of damage quickly.
This is your most important role, since you are effective with few items, and don't require any levels once your Imbue is maxed at level 13, you are open to fully control the meta game. There are several ways of doing it.
Awareness if first, and your heavy investment into Sight Wards will provide you with just that. But this goes much further than just giving vision of your enemy champions movement. Make sure to always ping opponents when they are closing in ona gank on one of your lanes. This will ensure a failed gank 100% of the time, as your allies will hear the loud ding and look at where is it coming from.
Control your team and opponents team, call for lane switches, let your carries free farm in a lane with you, harass your opponents and constantly zone them out. If one of your team mates seems to be doing poorly, don't shout at them, go into their lane and help them, Protect them and let them farm. Most of the time this result in a very strong champion after just 5-10 minutes.
Steal opponents Elder buffs every chance you get, with full awareness of everyone's location this shouldn't be a problem. Steal the dragon and Baron at every opportunity as well. After all you'll see if they are coming to kill you as you initiate.
Dominate the game you are in through sheer meta game presence. I have been called a map hacker by a lot of opponents in ranked matches. I've had oracles purchased to counter me (people give up after they get focus fired every single time they get it, also don't stop warding even if they do get an oracle, counter ward with Vision Wards if the opponent tries to get Sight Wards on you, trust me, your willingness to drop stupendous amounts of money and time on meta-game will deter most players from trying to outplay you in that sphere). Do this, and you will win majority of your matches. Even the most hopeless ones. All you need is one ace or near ace to win a game.
[E05]STRATEGY: Tips and Tricks
Taric has a fantastic harass strategy, that few Taric's actually use. Early on a combination of Dazzle > Run up to Shatter > Melee Hit will do a lot of damage that opponents don't expect. This can easily net you 400-500 damage per combo. The key is to run away right after the combo is done. Keep the fact that you have no significant persistent damage a secret. You want the opponents to remember you as a champion that dropped their health to half in a second, not one that took forever to kill them after.
You can backdoor a tower from 100% to 0% in about three tries (Using Stark's Fervor and Radiance). This seems like very slow and insignificant, but make a habbit of ocasionally back dooring a tower for some of it's health, even if you do not manage to take it down, distracting your oppoennts to come defend, is sometimes a very important tactic. Also you can easily take down towers at 1/3rd of their health. This may prove useful later on in the game.
Sometimes it is more beneficial to keep Shatter on yourself in order to provide the armor bonus for your allies, rather than using it as an AoE damage and debuff spell. Judge for yourself if this is the case in your particular situation.
Imbue can be used on your minions as well. This has several uses, early on if you are not getting harassed too much, you can mess around with your opponents last hitting by healing minions for which they go. You can also heal a minion while it is tanking a tower, to give yourself and your allies more time to do some damage to the tower. With a minion wave large enough you can do it several times. Remember that every hit on the tower decreases the cool down of your Imbue!