Single target I do fine, but AoE I struggle. I try to avoid ArcBarr cleaving to maintain 6 stacks. I tab target up to 3 mobs and throw in fire blast on cd (with the glyph of course to instantly trigger the secondary effect). I then throw in glyphed CoC on cd (increases dmg done on AoE by 200%).
Is this the proper way or are there other variables/conditions I should keep in mind?
I find that tab targeting nether tempest on everything and using the missile procs to generate charges followed by cleaving when either I'm at 6 stacks or I know I wont have time to do much else is a very efficient way of aoe'ing as arcane.
On 2-3 targets or targets that aren't grouped up tab nether tempest does fine. On multiple targets arcane barrage instead of scorch at 6 stacks is higher DPS (it's only like 600 less DPS on single target and arcane missiles doesn't cleave).
On ~6 target AoE like Wind Lord or something flamestrike on cooldown, use living bomb and the fire blast glyph, arcane explosion and use missile procs but cut them off to rapidly gain charges and arcane barrage at 6.
On ~20+ target AoE flamestrike on cooldown, frost bomb and arcane explosion. Arcane barrage when you hit six but don't go out of your way to get stacks.