As a general rule, the key I've found is to have a system in place that doesn't let things slip through the cracks without acknowledgement. It's fine to not complete something if it's less important than everything else, so long as you are making the conscious decision to do so. What you can't afford is to let something go by unnoticed that'll catch you off-guard. Practically what this means is having a place to record all of your outstanding tasks, a way of prioritizing them, and a regular review of those tasks. Tools like Shortcut, Jira, and Basecamp do this really well.
Also, keep notes and action items from meetings, and make sure to block off time to put those action items into whatever tool you use to track tasks. A lot of useful insight gets lost the moment a meeting ends if you don't!