Prepare a suitable text and then get some practice. Remember to:
- use a large, clear typeface and wide margins
- split the text into paragraphs
- highlight key or important phrases
- mark the points where you want to pause and look a bit longer at the audience
Then practise aloud until you are pronouncing everything correctly. After you’ve read it through a few times, start trying to take your eyes off the text and look up towards the end of sentences. In this way you will probably memorize whole chunks without even realizing. And remember to change your tone of voice, rhythm and speed according to the content.