Maybe it isn't strictly sticking to the definition of stoicism I've found this effective, surprisingly, in road rage or what some would call bullying situations. When someone is getting aggressive, I have just stayed serious, calm and looked slightly determined. I keep eye contact and try to think about being bored as well. When bully-types blow up at a stranger, they usually do it to someone that they think will back down. When they don't, they get confused.
Similarly I find it useful when some little thing is irritating me. I can't remember where I read it, I think it was related to Marcus Aurelius, but basically the idea that when something negative comes up, either say/do something, or let it go.
That person who just cut in line in front of you? Say something, or let it go. That guy on the plane obnoxiously tilting his seat way too far back? Say something or let it go.
As soon as I think that to myself, I let go and feel a wave of indifference and serenity.
These are of course pretty minor examples, but also really common everyday occurrences. Like, practice.
A gorilla could back up the initial bluff. I look pretty mild mannered but in my youth, I fought a lot in high school. In college and just after, I usually stayed out of it but there were quite a few of my buddies who took a bit longer to learn and thus quite a few weekends included a bar fight here or there. Point being that I'd try to avoid it but if a person moved the situation to a fight, I'm not tough guy but I can handle myself okay. Bullies don't often target someone they think might be able to handle them.
