Simple and straight to the point: go build a relationship.
Pick a friend that you don’t see enough, that co-worker you’ve been meaning to hang out with, that neighbour you just say hi to, anyone in your life that you’ve thought “I should spend some/more time with them.”
Invite them to your house, invite them out for drinks at the new place you’ve been meaning to try, accept their invitation to hang out finally.
At the core of compassion is love expressed in relationship. So go make or build some. Stop thinking about it and just go and do it.