Roaming Taric is probably one of the worst roamers. Taric doesnt need to farm a whole lot but really, his dazzle isn't good enough for him to be a good roamer like alistar or janna. Put Taric in lane were he can have some real use.
Taric gives whatever lane he's at great sustainability, and he can give whoever you put in lane with him (or himself) some kills, specialy if the enemy is dumb enough to towerdive him. He can push really hard with his ultimate and can work as an off tank or an AP support, which makes him heal squishies for for half their health bar or himself for even more, and his dazzle to hit harder then Sion's Q.
Be ready to use Q at all times and know how to use your E, and you'll be a good Taric. Don't be afraid to get an archangel's staff or mana items on him, as not only is Taric mana hungry, but mana almost work as effective health for him. Remember autoattacking reduces his heal's cooldown by 1 second on every strike.
His W is his least important spell, but take one level in it to help with farming. You can use it for extra damage later, remember it also debuffs armor. Don't use it as an actual damage spell unless you're really heavy into AP or still farming. The passive armor buff is much better then the AoE damage it does.
Just remember that Taric isn't good on all teams. Don't pick him if the team has no real tank, as taric isn't a real tank himself, he's a tanky support. Also, don't pick him if the team already has a stablished support champion, unless said support can deal some good damage (Zilean/Lux). Taric needs a team that can do nice damage, simply because he doesn't pack a whole lot of punch, even when dazzle is dealing over 700 damage.
Don't go full tank unless your team has no real tank, and don't go full AP unless you're pubstomping, go tanky support. My core build is (not exactly in this order) archangel's staff, banshee's veil, rod of ages and deathcap. You might wanna take some early armor if the enemy team is pretty heavy on AD though.