Is there really a social media etiquette when it comes to successfully marketing your business?

Is there really a social media etiquette when it comes to successfully marketing your business?
Go with a clean, uncluttered layout. Keep copy to the point, and try to stick to 3 colours.
Status updates on what you are doing, examples of work, media content, and how you can help.
We all use hashtags in our social media posts to get them more recognition. But are you actually doing more harm than good?