Sometimes the best thing you can do for a drought-stressed garden or landscape is to not do some things. Fertilizing and routine pruning, for instance, encourage new growth that requires more water. Fertilizing isn't wise during long dry periods if you can't water regularly.
Fertilizers are, chemically, salts.
They can actually dehydrate plants' roots. Routine pruning stimulates growth, too. That's not what you want when your main goal for your plants is survival. You may need to do some selective pruning, through when a plant wilts and begins to show leaf scorch, and branches begin to die. In this case, cutting back the top will reduce the water demand the foliage places on the roots.