her gun does jack stuff for damage
The primary does increasing damage the longer it's connected to someone, and the secondary (the electro-balls of doooooom) ignore barriers like Reinhardt's and Winston's, and can be spammed like a motherforgeter with shorter charges to, say, keep scaredy snipers from peeking out of doorways.
Basically if you're not setting up turrets or putting shields on teammates (25 regenerating health is REALLY useful, believe it or not), you should be spamming the secondary in the general direction of enemies.