Part of any good relationship is knowing when to talk and when not to. This is relevant to a good conversation too.
Make sure when trying to get a date, talk to someone that you are aware of the conversation and how the other person fits in.
A good conversation should not be one sided. Don't always talk about yourself as the other person may get bored. If they are not openly trying to add things to the conversation they may be a bit shy or not know much about what you are talking about.
Perhaps you can ask them some questions to try and get them into the conversation. Good questions are open ended, ie, not a simple yes or no answer. If you ask a person an open ended question then they will have to think about it and give more than a one word answer. Be sure to listen to the answer and perhaps ask another related question.
If you are on the other hand and are not doing much of the talking, perhaps you need to stop nodding (either asleep or with your head) and start asking some questions or adding your own theories.
Conversation is an art that gets better with practice and some thought.