First thing a Quote.
"A good Dominant does not need to blow his own trumpet-he "is" . He doesn't have to demand respect, he gets that anyway, he doesn't have to announce his reputation to the world who he is , because his reputation and respect of his peers proceeds him "
A good Dominant will not read a few pages on the internet, or look through a book then declare himself an experienced Sir with many years of experience. Good Dominants take Thier time to attend workshops, events to gain more knowledge.
A domineering person thinks that it is all about "being in charge" no matter what, often overbearing, loud, tyrannical they do control but in a oppressive way . A good Dominant exercises complete control in a more subtle way , with influences and thoughts .. he can be can be Authoritian and powerful but have the utmost respect for others and a high level of care and consideration , he takes responsibility for his submissive or submissives , he is Empathic and Sympathetic to Thier needs.
Submissives must be secure in Thier submission to Thier Dominant, on the other hand a Dominant is not to proud to ask for help or advice if needed . A good Dominant is sought for advice both from his peers and submissives, He is popular within the scene and makes time for everyone. He will never belittle others no matter what and treats all with respect .
A good Dominant is the one who is looked up to buy his peers and sought out by his peers and submissives, for friendship and advice .I could go on but that to me is the essence of a good Dominant, good Dominants also have longer dynamics with Thier submissive as she or he loves the way he Dominants.