How can you get people to listen to you?
Generally, listen to them so they feel you are interested in what they have to say, making them more likely to listen to you. Make eye contact so you know that they are paying attention. Maybe touch his or her arm gently. If there are other conversations taking place, wait for one of those lulls where the whole room is a bit quieter before you start talking. To get someone's attention who is already in a conversation, stand a polite distance away from them and look over at the person you want to speak with periodically, but don't stare him or her down.