We know from our nursery school days that the kids who most of the others (both kids and adults) liked had an easier time of it in life. Maybe they didn't get to the top like the bullies and the self-absorbed but they did well enough and on their terms, without a lot of drama. When bad things happened such as a death or job loss, support was right there, and from all corners.
Back in the late 1980s, Washington D.C. journalist Hedrick Smith analyzed likability as one source of power. It was not the only source but definitely a way to get, keep, and grow power. The book was "The Power Game."
Now, executive coach Michelle Tillis Lederman has provided more detail on how likability happens. Her book is "11 Laws of Likability." Most of the information is common sense to those of us who have observed professionals who have staying power in organizations as well as entrepreneurial life. They are likable because of the reasons Lederman points out. The strengths of the guide are the narratives illustrating what impedes or helps likability.
The "law" which I have found most useful is "listening." Once I began to do that when a prospect contacted me, instead of selling myself, more deals got closed. The days I am feeling insecure and work orders have been slow are those in which I tend not to listen. Of course, nothing good happens, not professionally, not personally. Obviously, I'm not likable.