i. If you can, find out a few things about the person before your actual start, in an un-creepy way. Kick off something interesting that's not too personal. "I saw that you're working on a pretty interesting project! How did you choose to?"

ii. Ask so that the other person can talk about him/herself. Identify things that you might be interested in hearing about, and politely ask questions, especially about their passions or their subjects of expertise.
*Ask for clarification. If your conversation partner is talking about an activity you do not understand, it's an opportunity to learn more.
*Be genuine.
*Use open-ended questions. Skip "yes/no" questions, ask instead for things that will allow your partner to talk extensively. "So you love to do X. What made you get into it in the first place?"
*Start superficial, and more generic. Then, gauge their comfort level. If it seems appropriate, then you can ask some more personal questions.

iii. Inject invitation and inspiration.
*"Invitation" happens when you say or ask something that lets your partner know that it's his or her turn to speak.
*"Inspiration" means that you come up with a great topic that makes your partner want to have a discussion. Share thoughts or stories with the goal to build an active discussion.

iv. Comment on a general interest topic. Like the current events section of the news for example - they can be both interesting and informative.

v. Listen actively. Never get too busy thinking of other things, including what you plan to say next. As a good listener, you identify questions to ask based on the other person's statements.
*Paraphrase back what you heard the person say. "So you're saying that X is the biggest rush you've ever experienced?" It is respectful, and gives him/her the chance to correct, affirm, or embellish upon your understanding.
*Encourage the other person to do most of the talking. Your partner may still feel you attentive and engaged, and you may get the credit for being a great conversationalist!

vi. Forget yourself. "It's much easier to become interested in others, than it is to convince them to be interested in you." When too busy thinking about oneself, or what the other person might be thinking, one won't relax. Discomfort is transmittable.

vii. Voice disagreement with respect. Acknowledge common ground before disagreeing. Try to omit the word "but" and substitute by "and" - many people find it less antagonistic.
Don't manipulate the talk to serve your own hidden agenda, or use it as a way to boost your ego.

viii. Accept occasional silence. Take a breath, drink or food bite while you think of the next thing that you want to say. Did anything create a new thought or topic? The pause serves a smooth transition into further talk.

ix. Tell stories, preferably funny. They are the spice of life. Don't be afraid to get some in your conversation.
*Take it slow, pause for dramatic effect when you need it. A steady, measured approach may draw it out and keep them enthralled.
*Transition into your story. "Funny you said that," or "Speaking of Y," or "Actually, something similar happened to me not too long ago" will help the story feel like a natural evolution of the conversation.
*Tell something that actually happened. A fabricated story just feels a little more empty than something that did happen.

x. Know when the conversation has ended. The best conversations also run out of steam or end by an interruption. Smile, state that you enjoyed it and say goodbye. Ending on a positive note will make the other person want to talk to you again.

From WikiHow's guide to conversation