All newly-planted plants need more water than they will later in their lives. Even plants billed as drought tolerant aren't macho during infancy and need special treatment their first summer.
Soil exposed to full sun dries out much faster than soil that is shaded or mulched. A few inches of mulch greatly slows evaporation from soil.
Focus on growing drought-tolerant plants. A number of beautiful plants, both native and non-native, can survive with less than an inch of water a week once established.
Place water-loving plants in areas that receive shade in the afternoon. Even sun-loving plants will do fine provided they receive morning to midday light. In fact, the harsh afternoon sun isn’t that great for most plants.
Create windbreaks, especially around vegetable gardens, to shelter plants and prevent drying.
Add hyrogels to plants that dry out quickly, whether in the garden or in containers. These water absorbing polymer crystals swell to several times their original size and slowly release water into the surrounding soil. Hyrogels can be found at your local garden center.
Mulch like crazy to slow the evaporation of moisture from the soil and to keep the soil cool. Try to stick with organic mulches that slowly break down and add organic matter to the soil.
Keep weeds out of flower and vegetable gardens. Weeds are notorious for stealing water away from other plants, so if you’ll keep their populations in check, you won’t have to water as often.
