It can be tempting, especially when starting out as a coach, to use lots of techniques, tools, psychometrics etc. But over time what most of us notice is that some of our very best sessions occur when we seem to have done very little and some of our least satisfactory when we have been very busy doing things with our clients.
In this, we can see a key quality of effective coaches, Presence. Presence is defined as "the ability to be with someone in such a way that that person comes to know themselves better". When we are fully present to someone we create a space where they are able to more fully be themselves and to have the experience of being valuable not for what they do but for who they are. You rarely see "Presence" on a list of coaching competencies but it is probably the most important of all.