This tutorial was helpful in that it talked about making sure to research the topic or topics you are going to be presenting and knowing key factors about the subject matter.  If a topic is too broad and has too much information, the audience tends to lose focus very quickly.  It's more important to stick to a smaller number of facts and keep the audience involved in the discussion.  I was also reminded to make eye contact, which I tend to struggle with.  Also, be prepared to answer questions and don't "fake" the answers.  If you don't have the answer, tell them you will find out what it is and get back to them as soon as possible and then follow thru!