I like how you have used the analogy. The language we use and the words we speak can build or destroy. We must choose wisely.

Two things I have focused on for the past year are,

1. to drop race terms when I am speaking about and to people. I believe the fewer 'categories' or 'groups' or 'collectives' I can put people in, the more alike we become. I believe we are all one spirit, so the way we look and the accent that we have, our political or religious affiliations do not define the 'who' that we are at a soul level. It takes a lot of mindfulness, but I can say that after doing this exercise for a year, it is becoming more and more natural.
2. I pay specific attention the language I use when speaking about a situation, event or encounter. I can not know another person's volition unless they tell me. So at no time can I speak about what they are thinking, feeling, planning, hoping and so on. This forces me to eliminate language that attributes motive and agenda about what a person has done or will do. It is the assumptions we make that can create conflict or peace, and it begins with our thoughts. This helps in a huge way to remove language of violence and conflict from my conversations. Much works still to do.
   Friendship.
   These are two small ways I am working on how I 'judge a book by it's cover.'