Keep follows/lists at 50 people or less of which no more than 10 are high volume tweeters. If people turn toxic, either mute them for a week or unfollow them if they keep it up.

It happens where a lot of people just have a bad week and need to rant, but it does get annoying. Doing it this way you won't lose out on insightful stuff they usually post and keeping the lists smaller gives you glimpses into area events or interests without drowning you.

EDIT: Also, add 'unroll' to your mute list.