dont pull huge melee mobs it will severely slow you down around 3-4 is the most efficient, except for burning forest where there is an abundance of ranged foes.
when you head onto battle field, pull 1 group of beserkers and the other group of casters only, than pop the shadows+ impaler up at the camp and 1 cast of sliver should mow down the beserkers, after that sliver down the shadows, 2 casts should do the job.
for burning forest make sure the healers are outside your agro bubble and use the right wall to your advantage, after that the rest is easy.
for tos, kill 3-4 abyssals/shadow patrols at a time, pulling more will severely slow you down unless of course you are able to block them against the wall than you can bring rad field.
make sure your sliver targets 1-2 shadow rangers at a time.
the rest is up to t2 triggering the mage straight away. and make sure your ebsoh does max damage as well.
you can take finish him or rad field if you feel you are struggling with battlefield or tos respectively.