Mindfulness teaches kids to focus on the present. Learning to adopt this practice can help children self-soothe in times they are feeling anxiety. There are lots of ways to practice mindfulness beyond breathing exercises. Being mindful can help kids build self-awareness and self-esteem. Mindfulness can look like taking a walk and intentionally focusing on nature or drawing and painting. Anything that allows the brain to focus intently on a single activity, all the while maintaining their breath.
You can find more resources about mindfulness from the following sites:
Note: Resources linked are not an official endorsement of the sites informational content