1. Model - this goes without saying for teaching any skill!
2. When you see someone demonstrating emphathy, point it out and praise them for it.
3. Set aside some time to teach emotions.
4. Get your students involved in the community.

Playing board games, watching a movie or using stories to discuss emotions with questions. Observe your students on the playground and use those "teachable moments" to point out feelings.

I love using picture books to teach empathy. The ones in this article have created great lessons and class discussions. This is a topic I revisit often.

https://selfsufficientkids.com/childrens-books-teach-empathy/