Evaporative cooling.
Cool, damp cloths, especially to place around your neck or on your face and wrists. Cool showers. Avoid any use of the oven and minimize use of the stovetop or any other device which produces a significant amount of heat. Keep blinds/curtains drawn while the sun is out. Open these and the windows at night. If there is any breeze and your home's layout is amenable, open windows to promote cross-flow. And, if safe, doors. Lightweight, breathable clothing. Avoid going out during the hottest part of the day unless it's to somewhere air conditioned. If you drive, try to park in the shade and cover your windows when parked to reflect sunlight. If public transit, heavier on the avoiding going out during the hottest part of the day. Hydrate. This means electrolytes, not just water. Cotton sheets can feel cooler than not using any bedding at all.