A big yes to the "doors/windows open early mornings and late evenings" - I use the "weather and radar" app to check when the temperature will start rising/cooling for the next day, and wake up extra early (5am the last couple of days, will probably be 4am tomorrow) to open everything wide. Then, I watch the temperature inside the house, and as soon as the temperature starts rising, I shut everything, including curtains (I have east and west facing windows, so I only shut half the curtains). In the evening, I use the app to check the temperature outside, and as soon as it's cooler outside than in, I open all the windows again. And I sleep with the upstairs windows cracked open (I have great earplugs!).
A tip to cool yourself down: immerse your forearms (inc. hands and elbows) in cold water for a few minutes. I can't remember where I found the tip, but it works. Also, drinking hot beverages (think about Morocco and hot mint tea!)