Use research to make your message believable to them. Speaking notes can be set up in a number of different ways. One of the ways is by writing out a script. It's a great way to make sure you say exactly what you want them to know. A script, however, does result in poor eye contact, and you risk sounding dull.
Brief notes are a better form.
They give an informal structure to your presentation, allowing you to fill in the informal words between the formal ideas that you wish to convey. Your notes should be easily read, very brief, with no more than one idea on a card. Some parts of the body of your presentation should be memorized. Reading essential information to an audience, rather than having it memorized, erodes your credibility. You want to convey that you know the information without having to look at notes.