Design Thinking is a "creative process that helps designs meaningful solutions in the classroom, at school an in a community." (taken from https://designthinkingforeducators.com/)
A great resource to get started with more design thinking is the Design Squad from PBS Kids. The site contains videos, design plans and list, and even some problem solving games. Try it out. http://pbskids.org/designsquad/ Some examples are listed below.
You can build a magnetic field detector. The instructions and materials list are at http://pbskids.org/designsquad/build/inspector-detector/
You can build a shock absorbing system that can protect "astronauts". http://pbskids.org/designsquad/build/touchdown/
Build a hovercraft and learn about friction and thrust. http://pbskids.org/designsquad/build/hovercraft/