With air-pocketed ice, hook the pockets. Chandeliered ice, comprised of tiny fused icicles, demands hooking, delicate movement, and diligent searching for protection. The crux is finding solid gear placements. Climbing bad ice is like climbing bad rock. Stay focused and constantly assess the medium.
Every move is another judgement call.
Tool testing questionable placements bolsters confidence and prevents falling. Before you even touch the ice, though, you have to make a realistic decision whether the climb is safe, given your experience level and the current conditions of the route. Bailing has no shame. It's not worth dying for.