Keep the environment around cool
I like to separate two different subjects and explain each differently.
First the environment around us like our home and secondly our body and how we control the heat within our body.
Talking about our living space, every home is different but the first thing we should do is to minimize sun exposure coming into our living space. Where our home is exposed to the sun is through walls, ceilings, and windows. We might not be able to do much with our walls and roof if we live in a condo, apartment, or townhomes, but if we live in a house by adding more insulation on the roof, we are doing good for our wallet in the long run because it will keep the house warm in winter and cooler in summer. Most sun heat comes through the windows and that is where we should control by a thick curtain. If we don’t have a thick curtain which most the new homes don’t you can hang a blanket for the time of the day that the sun has the most heat which is between 11:00 am to 6:00 pm
I’ve seen some people stick foil paper or a reflective wrap on their windows. This method is a very low-cost solution as well. This way the sunray will be reflected outside and won’t heat your room either. You can make tape it in a way that you could remove it when you want the sun to come through.
Air Flow,
We should create constant airflow so that to make it much more livable. If there is some winds or breeze from outside, you can have the windows open (make sure the blanket hanging won’t stop the airflow)
If the outside breeze is not substantial, a ceiling fan or a portable fan would do the job. You can have the bathroom fan and the kitchen hood fan to run as well.
Putting a bowl of ice in front of the fan makes a huge difference to cool down the room temperature.
Cooldown the exterior of the building,
If you are not under the water restriction, it is a good idea to water the exterior surface of the house after 7:00 PM when the sun is reducing the angle. The house has collected the heat of the sun all day and it is cooking. Water will cool off the exterior surface and will reduce the interior temperature by 5 degrees so you can sleep in your house at night.