[Manic]

When I started my warlock I was in the same situation for a long time and then one day it just clicked. Give it some time, it's a practiced technique.

Although opinions vary, I personally prefer the VW for multiple mobs.

One thing I would stress is to always keep moving, constantly repositioning yourself to keep distance from the mobs. The only time I am not moving around is when I need to cast a non-instant dot (or draining life/drain soul to top off mana at the end of a fight)

I've rerolled an undead warlock who is currently 43 and am having great success with multiple mobs, again mostly due to the fact I've had so much practice.