Durring early game Tarric is not so tanky as in mid or late game, so just try hiding in bush, clear wards and just save mana so you can have enough to protect your carry if needed or ganked. Try stunnig only when needed or when your target is in range of your carry. Avoid stunning tanky supports so you can have cd for the enemy adc, but always prioritize your carry safty :)
DO NOT RUSH CASTING YOUR SHATTER! IT'S IMPORTANT FOR YOUR CARRY SUSTAIN IN FIGHT!