Pros

Her passive lets her ap surpass mages with ap items early game
She can turn a good defense into a powerful offense
She has her ult at level 1
She can level up her abilities to 6
Quite tanky
Doesn't need to facecheck bush to finish off enemies recalling in it
A descent chaser
Two of her abilities do no need a target to activate it (Beware stealth champs!)
Fires off heals and sheild while hurting enemies
Uses minions and wards to turn into a long range champion

First let me start out with initiating a fight to the side of mid-lane in the bush. Don't start attacking until when they get in the bush otherwise they might get away. If she has the element of suprise then she has already won. This obviously means you must buy and move quickly if you wanna get to the brush before your adversary. Ok now, why you wanna start out with a long sword first is because her passive takes care of her ap, plus her spells have long cooldowns. So you wanna continue fighting after her mantra-empowered sheild has done it's damage.