You can also add in some of this if they continuously do it:
I will admit sometimes I have a bad habit of interrupting (or as I like to call it "enthusiastically interjecting".), but I recognize it very soon after I do it, and apologize as quickly as possible, and extend my ear to the other person so they can finish telling their story.
I have friends that constantly interrupt though, and then talk to each other. Then I'll add to the conversation and they'll ignore me, or ask me to repeat myself for like the third time because none of them were listening. Sometimes I feel invisible.
Then they ask me why I'm being so quiet and I start feeling homicidal.