How do I become more articulate?

Stop trying so hard. Mastery of language comes with age and conversational experience. While you may have a reasonable grasp of the words you are stringing together to sound articulate, you may still be lacking the real world experience to effectively utilize your vocabulary. Which, in turn may make you look like a total prick to the people around you. I'm not saying to dumb it down, just that you should try to learn to play your audience. Try to appeal to your audiences (who cares how many there are?) sense of humor.