Continuous Improvement is more than just a phrase or a buzzword, it is the key to a useful dashboard. You should not iterate for the sake of iteration. Iteration should be informed by feedback from consumers of the dashboard and the Point Person of the dashboard.
Collecting timely feedback from the users and consumers of your dashboard will help you improve the dashboard. There are a few options for opening feedback channels that you may wish to investigate.
You will want to open some kind of easy, written feedback avenue, to give users a place to comment, offer suggestions, and ask questions. Providing your email or slack username allows for quick communication but can get overwhelming. A tool like Google forms captures feedback into a sheet that you can review as needed. For clear tracking, you can go with a tool like JIRA and have people submit tickets when they have feedback. As the amount of effort increases to send feedback, the less likely you will get feedback so make it easy.
Everyone knows that a person is most motivated to provide feedback when things are going wrong. This type of feedback is powerful, but not always constructive. It is helpful to focus on the source of their frustration. Is it a design choice, is it the data, is it not useful for them, or are they having a bad day? Consider their feedback and weigh it against the purpose of the dashboard and make a decision. The best thing you can do to encourage higher quality feedback is to let the person who gave you the feedback know what you decided to do about with their feedback
A common type of negative feedback is that something isn't working properly on the dashboard. This is a different type of feedback and it should be marked to grab your attention. Create naming standards for this type of issue such as: Place [BUG] or [BROKEN] at the beginning of your feedback so you can prioritize the fix. In some tools, you can accomplish this by tagging the feedback.
Moving your audience from a one way feedback channel to a community can unearth more valuable feedback. Use a community building tool like Slack, to get an insight into how viewers are talking about your dashboard with other viewers. These discussions will often provide more candid feedback. You can also solicit feedback on these channels. Once a person chimes in others who are experiencing the same issues will tend to pipe in so you can judge the significance of the issue.Consumer support
Set up an iteration schedule where you review the feedback you have received. A regular interval such as every month or every week works best. It is better to review feedback (other than bug/broken feedback items) on a schedule instead of ad hoc. This gives you the opportunity to prioritize your work and see if there are themes in the feedback.
Create a checklist, similar to the below, to review the dashboard in the scheduled review session.
Adoption and usefulness metrics of the dashboard