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.
Be consistent with your own voice across your posts and engagement.
Status updates on what you are doing, examples of work, media content, and how you can help.
If you are just starting out, pick one or two platforms to concentrate on initially.
Post varied content types. Video is King, but also utilise graphics, photos, GIF’s, and more.
We all use hashtags in our social media posts to get them more recognition. But are you actually doing more harm than good?