Look at your curtains. If they are light, impervious to light, replace them. Purchase, for example, blinds that completely cover the window, allowing you to dispense sunlight. These curtains are made of light diffusing, blackout and reflective fabrics.
Another good way to lower the temperature – cassette blinds. Such devices are mounted on the sash, which access to the window is always open.
The third option - reflective (heat) film on glass. It reflects infrared rays, it reduces the flow of solar heat and does not affect the illumination of the room.
Ventilation is a good way to cool the room, but open Windows need just at the right time. Keep Windows closed in the afternoon, in order not to let the dust and hot air from outside. To ventilate the apartment only in the morning or late in the evening.
Remove all unnecessary things, for example, carpets from the floor. You agree that in the heat to walking in them not too nice, but on the bare floor cool - very even. You might also shake out the rug or send it to the cleaners. Picture frames, and other Souvenirs in the heat turn into dust collectors. You should remove them on time - so you reduce the percentage of the settling dust, that is, breathing will get easier.
From time to time moisten the air in the room at least with a conventional sprayer. You can add the water a few drops of citrus or mint flavoring. It is best to humidify the room with cold water every morning. Or buy and install a humidifier - it will purify the air from dust and microbes gather.
Worth keeping an eye on the number of electrical appliances, because when the work they generate heat. Even included light sets it off, not to mention, say, of computer. Cook on the stove or in the oven less than usual, not to raise the temperature of the air in the kitchen . If you must heat food, it is better to do it in the microwave. In General, in the hot summer days, doctors recommend to give preference to fruits and salads.