It's important for children to understand their identity and values to help them to understand themselves. There's a video for children to start thinking about their identity and their values here. 

For older children, helping them to develop self-awareness can be a good way to encourage them to know and understand themselves in the school environment. There is a worksheet that can used as a prompt here. 

Other resources 

Supporting children's emotions in EYFS 

Understanding children’s emotions is important in understanding how they are behaving. Children in EYFS often feel lots of different emotions, but do not know how to express, understand or process them like older children and adults. Behaviour can be a way that young children express their feelings and emotions. To support children to understand this, approach them with empathy, guide them to label their emotion/feeling, and support them in problem solving.

Source: Education.gov

The video below includes RULER, an acronym for Recognising, Understanding, Labelling, Expressing and, Regulating emotions, which is a framework for teachers to model and teach emotional literacy. 

https://www.youtube.com/watch?v=b7M3OPA2lZI

Activities to try: 

CBeebies: How to talk to your child about emotions.

Feeling Better: short videos about different feelings, using puppets.

What are feelings? Dealing with feelings, and recognising others’ feelings.

The Age of Emotions: podcast discussion on emotion culture, with psychotherapist Philippa Perry.

Word of Mouth: Naming Emotions: Michael Rosen podcast, about describing feelings.