Besides just focusing on one mob, it really pays off to focus
on the *strongest* mob first. There are alot of reasons for this
but in the case of lullaby it's more likely to work on the
weaker mobs and make them stand there waiting their turn to
get beat on. If your group is smart (or well informed by you -
I usually say inc and call first target when I'm pulling), this
should let you control the fight very nicely. I'm fighting
tougher stuff these days but many times I had a lizard defender
and maybe a couple warders sleeping away while we wailed on
the tougher sentinel in Cazic. Lullaby can turn an un-winnable
fight into a near cake walk if you have some luck on your side
and dont get too many resists.

Berk, level 25 bard, Rallos Zek