Research people with whom you have any kind of business relationship. This is not as sinister as it sounds but means that you can note their interests and concerns and find out what makes them tick.
Keep up to date with issues for your industry. There is any number of special interest groups and joining relevant ones can be extremely informative.
Contribute to discussions if you have something to say. Such comment can help to position you as someone of interest and/or knowledge in your target sectors.
Remember that competitors will check your social media accounts as well as your friends, connections or followers. If you become newsworthy for any reason, good or bad, your accounts will also be a first port of call for journalists.
Disparage competitors, even if they disparage you!
Be glib about news stories – although thoughtful comment is positive
Use status updates to advertise your products or services – it is a turn-off for readers who will probably simply block your posts. There are ways to advertise on social media but that’s a whole different story.
It should be obvious but swearing is not acceptable
Post after several glasses of wine – it loosens the wheels of the brain and once you’ve hit “post” it is too late!