I also want to learn how to be kinder. The sticking point, for me, is better prediction about what makes people feel good. I was very ill a year ago, and at that time learned a great deal about how comforting it is to be taken care of by someone who is compassionate and knowledgeable about my condition. But for me, unless I'm very familiar with that exact situation, I have trouble anticipating what will make someone feel better. This is also true in everyday situations. I work on figuring out how to make guests feel better in my home and how to make a host feel better when I'm the guest. (I already know that my naturally overly-analytic, overly-accommodating manner is not most effective.) I observe other people carefully, but it all seems very complex and I consider myself learning and a 'beginner' -- far behind someone who is more natural at this.

In addition to seconding nonviolent communication, cognitive behavior therapy techniques are pretty good - basically mindfulness exercises and introspection. If you want to change how you respond to certain situations (e.g. times when you get angry, or times when you have an opportunity to do something nice), you can start by practicing awareness of those situations, e.g. by keeping a pencil and piece of paper in your pocket and making a check mark when the situation occurs.