Not long ago, on a panel, I mentioned that artists are people and people have lives outside of their work. Fans are interested in those lives because they are also people. So if all you ever talk about is your work, you seemingly lead a very dull life. Therefore, when I see artists I follow putting up post after post of:
"Here's my new track"
"I'm playing here"
"I just posted a new photo"
"Please buy my..."
I get bored very quickly, and I tend to gloss over their entries.
The most successful people online are those who not only have something to say, but those who branch out from their day job and are willing to engage people in discussions about things that have nothing to do with what they are working on.
Next time you plan on making a post, consider talking about your favorite restaurants, foods, tips on traveling (if you tour you have lots of experience), where you shop, your strengths, weaknesses, who you admire, favorite books, movies, where you grew up, childhood memories, favorite lyrics, how you came up with a song idea, news items, pet peeves, etc.
These topics help drive conversation. No one cares about PR speak. They want the real you. Deliver that experience and you'll have a more engaged audience who actually cares about your continued success, because they feel vested in who you are.
Oh and if you are in a band, make sure everyone participates. Nothing feels more staged than the feeling that everything emanates from a single source.