Ian Betteridge (of Betteridge's Law fame) once described this to me as "Journalists pick up the phone": which is to say, if you're claiming to be committing journalism, you call (or message) everyone that you're talking about -- for comment, for their side of the story, to correct or challenge your facts.

It's pretty unpleasant and chastening a lot of the time, and you have to develop a hard skin for cold-calling and being blown off, or having people vent at you. But if you don't do it, you don't know all the angles, and you haven't finished your job.