Aerate and/or dethatch as needed. Aeration in the early spring along with a good pre-emergent fertilizer will set the soil up for a healthy season. When there's residual leaves and dead grass left over from the previous fall as well as compacted soil from the winter, nutrients, oxygen, and light have a harder time reaching the soil and roots. Aeration will penetrate the soil and open up pathways for nutrient transport.
Apply a good high nitrogen fertilizer as well as a high iron fertilizer to further prepare soil for health throughout the season by supplying critical nutrients.
Water 3x per week at about 10 minutes per zone as opposed to everyday at shorter time spans such as 5 minutes. Watering in the early morning before sunrise is recommended as opposed to the evening or during the day. In the early morning, the soil has time to absorb the water before it evaporates and this moisture will help protect the soil from the summer heat.
If water cost is an issue, dial it down to 2x per week but prevent from not watering at all as the lawn will eventually go dormant if there's not enough rain.
During the summer, especially if it's extremely hot and dry without rain for several weeks, it's best to keep your lawn cut higher (4 inches for example). This will help protect the soil from the heat as well as encourage deeper and more robust root growth. Higher cutting length = deeper root growth. Frequent cutting at short lengths = shallow root growth.
A high potash fertilizer applied during the early summer along with watering 3x per week will help prevent summer burning or yellowing of the grass due to excessive heat as shown in photo above.
The grass is under enough stress during the summer mostly due to the intense heat. Avoid additional stresses such as excessive foot traffic, mowing too frequently (more than once a week), or mowing too short.