Do retrospectives at regular intervals and encourage everyone in the team to bring up (almost) any issues, large or small, in those meetings, and discuss them,

Do retrospectives at regular intervals and encourage everyone in the team to bring up (almost) any issues, large or small, in those meetings, and discuss them, with a solution-focused outlook - what can we actually try in order to address this problem? An essential feature of retrospectives is that upper management, and internal/external customers, are not invited - and do not get to see the raw whiteboard, but only - if they see anything from it - a sanitised summary that's relevant - and diplomatic - for them. This all helps to encourage openness.