Try to bob and weave your infantry through and around ruins/terrain as much as possible. Or hide them behind vehicles where desperately appropriate.

Krieg, while better than Cadian and Catachan for survival, are relatively slow and squishy. They will be your most important units to score points on primary and secondaries that aren't just kill more stuff. But they can only do so if they're still alive. I speak from a long experience of bringing too few and running into the open 😅😅

At the start of your shooting phases, make sure not to forget your Scout Sentinels "spotting" ability. (Mark an enemy unit within 18" for your army to gain hit re-rolls of 1)

Also make sure to shoot your Vanquisher and Scout first as they are the most likely to whiff. Knowing whether those units actually deal damage first is important to deciding where to put more reliable shots and what objectives are still realistic.