Wow, that takes me back years to when my sister and I were teenagers and dating. (Well, I was sort of pretending to date, but that's another story.)
Mom said she only had one piece of advice for both of us when it came to trying to impress a date or a potential friend: don't. She said if we find ourselves talking about ourselves most of the time, we're doing it wrong.
Be interested in the person you're with and expect them to be interested in you. If it doesn't go both ways, move on.
She learned that the hard way, but that's another story too.