I have learned that in communication these elements are always present: sender, message, receiver. In one-on-one communication, there is always the speaker, the message, and the listener. One can never have an effective communication if there is no clear message and no proper listening. Meaning, if two persons are talking at the same time, there can be no effective communication. At some point, a person should first listen to the other who is talking. If the other finishes, then the listener can now act as the speaker, and vice versa. But there are also instances that, for example, an idea popped out in your head and you readily want to say it without even waiting for the right time to speak up. It's always good to say what's on your mind but its better if you grab the chance to talk in the right time. This kind of attitude shows that we are a good communicator.
I have also learned that the proper conveying of the meaning of words is appropriate. If two people are talking about something, and it also happens that another person is listening, it helps if they make an atmosphere of familiarization. For example, my brother and I were talking about "language". We were asking each other, what kind of language is the best to use when creating a thesis in Information Technology. The term has a different meaning in IT, so when IT people talk about language, they are referring to "programming language", which is a software used to create programs and applications. My mother butted in and said "I can use the English language." My brother and I looked at each and laughed. But then we explained to her what we were really talking about.
I guess it's also important to watch our tone when speaking. Tones convey different meaning for different type of listeners. A person can have a low tone or soft tone just to not show that he is angry or irritated. We don't want to mess up with other people's feelings just because they cannot easily grasp what we are trying to say.
I guess it also helps if we give examples when we are explaining. People easily understand what we mean if we provide illustrations.
By the way, it's also good to remember that to start a conversion, its always nice to have a topic that the other person is most interested in.
And lastly, always face the person you are talking to. When you do eye contact, it makes the other person feel important. It's also good that when you listen, you nod as a form of acknowlegment and at times ask questions about what they saying. This will make them feel that you are really interested. Just a note, do not get physically too close, cause this might convey a different perception.