A strong fertilizer and weed program is maximized with an equivalent watering strategy. Deep watering stimulates root growth and develops thicker turf. Water in the morning, as opposed to night or afternoon, to avoid disease issues and evaporation waste that occurs in the heat of the day.
Keep mowing heights close to 3"+ during warm months. This keeps the soil temperatures cooler, less stress on the turf, and increases a healthier root system. Cut the top 1/3 of the blades to keep deep green color.
Finally, maintain a balanced "diet" for your lawn by giving it all the nutrients it needs through a year. The temptation is to skip a step because the grass is looking good. But that's like skipping a meal. But these meals are spaced out between 5-8 weeks!