Awnings, screen doors, open porches and gazebos.
Wear a wide brimmed hat outside, it keeps the sun off your head and neck. This helps prevent heat strokes.
Wear loose clothing (white cotton?) which the breeze can blow through but still shades you from the sun. You want the cooling effect from the sweat evaporating off your skin.

Plenty of cold water to drink and cool swimming holes when needed.
It can be surprising how much better a cool shower or bath can make you feel on a hot day. Even splashing cold water on the forearms (the insides of the elbows where the skin is thin) will help cool you off a lot on a hot day.

Another help is to eat lots of melons.
Muskmelons seem to help a person stay cool the best.

Hot peppers also help even out the circulatory system when it is hot out.

Salt can help if you are sweating a lot, but only enough that it quits tasting sweet to you when licked off the palm of your hand.
(When you are short of salt it does not taste salty, if it tastes salty you have more than enough in you already.)

Plant more trees if you can.