NLP began by modelling excellence. To enhance your skills, follow the example of NLP's founders: find the top performers in the field and become curious about what they do and how they think. Chapter 11 explains more about modelling.
Use a framework such as the NLP Logical Levels to observe how coaches operate at each level, from the environment in which they work, right up to their sense of purpose. Turn to Chapter 5 for a quick review of questions to ask at the different logical levels.
When Richard Bandler and John Grinder modelled the great therapists, they found that one model of excellence wasn't enough. Each of their exemplars achieved results in his or her own unique way. So choose two or three different people to model who come from a variety of backgrounds. Create your own model of what works for you.
You can also refine your skills by attending master classes and teleclasses from top coaches. Look for offerings through coaching associations or watch videos of their work.