Presentations are usually divided into 3 different parts + a questions round:

-Introduction: tell your audience what your message is going to be.
-welcome your audience
-introduce your subject
-outline the structure of your presentation
-give instructions about questions

-Body: tell your audience your real message.
-do not hurry
-be enthusiastic
-give time on visuals
-maintain eye contact
-modulate your voice
-look friendly
-keep to your structure
-use your notes
-signpost throughout
-remain polite when dealing with difficult questions

-Conclusion: summarize what your message was.
-Sum up
-(Give recommendations if appropriate)
-Thank your audience
-Invite questions

As a general rule in communication, repetition is valuable. In presentations, there is a golden rule about repetition:

"-Say what you are going to say,
-say it,
-then say what you have just said."

This table shows examples of language which may be used in presentation when: