Fellow wizards, how to remain an asset in groups?

[Aborath]

I know, I know; wizards should be quadding. But what about those times when all the good quad locations are camped, or you just feel like grouping instead? How do you make yourselves an asset to the group--and not a fifth wheel. I ask because this is the way that I often feel when grouped. Sure, I nuke, root, stun, etc. as required, but eventually my mana tank hits "e" and I'm forced to sit and med, nuke once in a while, but otherwise be perpetually at 10% mana. Meanwhile, waves of melee damage are just scrolling by while I look on in quiet envy. So does anyone have tips on what I might do extend my usefulness? For example, how should grouping wizards nuke? Just spam our most mana-efficient nuke 1-2 a fight (ex., Coinflag, IC)?