The only way I've been able to control toxic people in my life is through elimination. As a manager of people, if you do not pinpoint the toxicity and remove the problem, it will only fester and overflow onto others. One toxic person can ruin an entire team through poor morale and negative thinking. I find that I apply this same mindset to my personal life with great results. Far less stress.

just keep them away and things will work out for you, leave all that behind...

I divide my toxicity between people at work and family/friends.

I think toxic family & friends are more difficult to deal with, especially siblings, because one's psychic buffer is usually well worn and it doesn't take much to start reacting. In these cases, I focus on behaviors. I reward or acknowledge good behaviors and either confront or ignore the person during "bad" behaviors.

I employed slightly more creative options at work. I restricted one woman to e-mail after I got tired of her nastiness on the phone. If she called, I'd let it go to v-mail and reply via e-mail. With our department director (the child of an alchoholic parent and certified crazymaker), I eventually figured out to just assume she was nuts. Once I did that, I was never surprised by her behavior.

Lastly, maybe I'd take a page out of the "Intervention" tv show playbook. That being, if things are unbearable, maybe confronting that person and saying that you care, but can't be around their toxicity is the solution.

I concentrate on building a really strong family. My immediate family, which is my husband and daughter, is everything to me. I eliminate anyone whose toxic behavior affects my mood or happiness at home.

I aviod them and in time they vanish from my life.

My husband set up a special email file called "confusing", and when the people, or at the time, the person, sent me crazymaking emails, he taught me to
immediately put it unread into the "confusing" file and read it after I'd dealt with all the
viable ones. This way if I took an email out of the "confusing" file, as opposed to the normal-people's-email inbox, I knew what I was getting into. It seemed to work, even though it's a mindgame. This taught me to mentally put crazed other behavior into a mental "confusing" file so I can deal with it only when I have a clear mental desk; it's labelled and I know it will require special treatment.
Because crazy people are lonely, they hope to make us crazy too. It won't help them; don't go there. It's sad but.

As a divorce attorney, contact with "toxic" people was an unavoidable part of my job. I found that treating "toxic" people with unrelenting good cheer and kindness was most effective. If they respond with hostility, it is clear to everyone else who the insane person is. Frequently, the sheer perkiness of your every response will either bring them around or else at least prevent them from tainting you. And for those so committed to negativity that no amount of sunshine can lighten their day, remaining bright and cheerful really irritates them. And that itself can be amusing.