Double-layered roofs are a really easy way to avoid daytime heat gain, and a slightly more sophisticated design minimizes nighttime heat losses too.

Here's a tropical house with multiple roof layers to stay cool: https://www.notechmagazine.com/2013/09/a-passively-cooled-ho...

https://wattsupwiththat.com/2012/09/12/something-practical-n... or the paper: http://callippe.com/blog/wp-content/uploads/2012/09/ORNL_roo...