Give the speaker your full attention. This means sitting up in your chair, leaning forward, making eye contact and nodding where appropriate. Active listeners look like they're listening. The more effort you put into listening, the more likely you are to pay attention to what the speaker says.
React with appropriate verbal cues, such as "Yes," "Really?" or "OK." These demonstrate to your speaker that you are following what they are saying. To know when to say these phrases, you need to be listening carefully.
Ask questions of clarification when necessary. Ask the speaker to repeat a point you missed. Paraphrase an idea in your own words to make sure you understand. This also demonstrates to the speaker that he has your full attention.
Take notes as you listen. Write down the overall idea that the speaker expresses, as well as any other major points. Write down questions you want to ask when the speaker pauses, or circle a statement you don't understand. Interpret what you hear as you go along. Write "Must have been happening for awhile" or "agree."
Switch roles with your partner and take your turn at speaking while he listens.