@GreenRoc Some tips...
Tinfoil on windows can reflect sunlight away. Just spray with a mix of dishsoap and water, apply foil with the shinnier side out. If being held on by soap means it's easy to undo later.
A blanket behind your curtains will also slow heat gain (and loss in the winter!)
Heat rizes. Use this knowledge to your advantage.
Exhaust heat from the highest point you can, and draw air in on a lower window n the shadier side of your dwelling.