Prior to actually presenting, you should have already planned, prepared, and practiced your presentation. When it actually comes time to present, your audience deserves a speaker who is prepared, punctual, and keeps to the allotted time (if any). Dress appropriately based on the type of presentation and the audience.
Start your presentation off right by making a good first impression. Establish eye contact, be as relaxed as you can, and try to be enthusiastic. If you do not have a microphone, be sure to speak loudly enough so that you will be easily heard. During your presentation, use the tips previously given for the 7 Cs of communication, such as being clear, concise, concrete, courteous, considerate, correct, and complete.
If something goes wrong during the presentation, do not panic. Do your best to recover and move forward. Try to conclude your presentation on a positive note so that the audience can leave with an upbeat impression.