There are different versions of this fight. The strategy will vary according to the area in which the two spawn:
The Deep Quarry: At certain points in the fight, Cugdava (golem form) becomes indestructible. You get a message that a crusher has become active. Lead Cugdava under the lifted crusher. Some bits will spawn. Repeat as needed.
Forge of Brell: Killing Cugdava'sundead warsmiths causes her armor to be destroyed or damaged. Use cautious body pulls to get just a couple of warsmiths at a time. When all the warsmiths are dead, kill Cugdava, then Gavitzle.