We are getting prepared for school next week by doing three days of "Bootcamp". The idea is to get the kids back into learning mode after several weeks of relaxing. So I decided to talk with them about growth mindset and how it helps us approach difficult things in life. Instead of flat-out refusing to do a task because it is too difficult, I encouraged the kids to start using the tiny word "yet" more often. (Think: "I cannot do this yet.") This way, challenging situations appear less fixed and more do-able on the long run.
In order to make the concept of "growth mindset" more concrete, I had my kids complete and color a little worksheet on the various things that make our brains (even adult brains!) "grow": music, healthy food, sleep ...
If you are more interested in growth mindset and how to teach it to kids, I can highly recommend the website Big Life Journal. I have not purchased any products from them - yet ;) - but I find their articles and materials always inspiring.