Enclose your phone into a Faraday cage and block all incoming and outgoing signals! Smartphones constantly send out signals that allow companies and governemnts to track our movements. As descriped on their website "Kill Your Phone comes to fix this issue with an open workshop format for hackactivists. Using their toolkit you can build your own Faraday cage or run your workshop and invite participants to make their own signal blocking phone pouch. In the pouch the phone can't send or receive any signals. It's dead!"