Pop open "filter preferences" in adblock plus, and add the following rules to hide mentions from people who don't follow you (and who you don't follow).
For the interactions/notifications page:
twitter.com##.interaction-page [data-follows-you="false"][data-you-follow="false"]:not(.my-tweet)
For the mentions page:
twitter.com##.mentions-page [data-follows-you="false"][data-you-follow="false"]:not(.my-tweet)