* never "watch" a repo/org for any activity. That just subscribes you to all issues/PRs and it's absolute hell. If you unwatch, you will get automatically subscribed whenever you are the author, get mentioned or someone requests your reviews

* manually unsubscribe from issues/PRs when you think you probably won't have anything else to add

* just focus on github.com/pulls/review-requested as your "work queue"

* have dedicated chat channels where people can ping you if you really needed

* if you go away for awhile, mark your github status as busy so that no one can request a review from you