The habit of focus starts with being aware of a person’s presence, listening to what they say and comprehending their meaning.
Then the listening becomes focused. You’d be amazed at the effect this had on people. I started a conversation with a blind man once. I approached him, and when he spoke I would follow it.
He had told me a story, and I followed it. He paused and I waited for him to go on. I’d responded when he did, and he’d replied.
It didn’t matter if it was one word or two, five or ten. That’s the gist of what I believe I was doing, and it worked well.