Etiquette is an art form. There are as many facets to etiquette as there are opinions about the interpretation of its guidelines. Alternatively, protocol is a science. It's exact.
You can find lots of examples of contradicting etiquette advice, so what or who should you trust? The best information is to choose a particular philosophy or school of thought and stick with it.
I subscribe to Debrett's philosophy of etiquette. Debrett's has been publishing about and teaching proper etiquette in London since 1769. I share the general sentiment about etiquette as detailed in Debrett’s Handbook, published by Debrett’s Limited, London, 2018: "The essence of good manners is to treat other people as you would wish to be treated yourself, to show empathy, so that one feels confused, excluded, or exposed."
However, there are many good etiquette books available. Most are specific and explain table manners, for example. Others try to generalize and cover many topics. These tend to spread the topic so thinly they become less valuable in an earnest pursuit to master etiquette.
I highly recommend Debrett's Handbook, British Style, Correct Form, Modern Manners, version 2018, as the gold standard of all-in-one etiquette books. This book will teach you the proper way to address others, invitations, dress codes, weddings, introductions, and table manners.
If you would like to understand the origin of modern etiquette, then read The Book of the Courtier, written in Italy by Baldassare Castiglione, and first published in 1528. The book is an essay, a "how-to" for Italian nobility members during the Italian Renaissance. It is a fun read and offers many etiquette tips that are still pertinent today.
There are tips for ladies and gentlemen, including a dance tip for men to help them “To dance well without over nimble footings or too busy tricks." The author explained the term, "Sprezzatura," "an easy manner that conceals the labor behind those carefully cultivated skills, is the hallmark of true refinement." In other words, act like Beyonce: "I woke up like this."
You can find "Sprezza" for short in many forms. There are variations for gentlemen's fashion as well as lifestyle items, a subscription service, Sprezzabox, for restaurants, magazines, and more.
Or, to really dig into the facets of etiquette that will be most applicable for your particular personal and professional development, hire a proper etiquette coach — I would love to help you — or you can always read up, and pull it all off with sprezzatura!