Make a good set of notes you can follow at a glance, and PRACTICE your presentation.
Dress for the occasion and tidy yourself up. Do something about hair that tends to fall into your face. Avoid wearing a hat or cap because it can obscure your face.
Arrange the environment to suit your presentation and get rid of distractions—erase needless information from the boards, turn off equipment you're not going to use, close or open windows, blinds, and doors to aid audience visibility, hearing, and comfort. Turn on enough light so people can adequately see you, your eyes, and your facial expressions.
Check the operation of audiovisual equipment before your presentation. Have a backup plan in case it fails.
Make sure your notes and other materials are in proper order before you begin.
Get rid of any gum or food you might have in your mouth. Don't hold a pen or paper clip or anything else that you might twiddle and distract your listeners.
Stand or sit up straight with your weight balanced. Avoid slumping, twisting, or leaning on the lectern, table, or computer console. Don't stand in the light from the projector.
Make eye contact before you start to speak, as you normally do in beginning a conversation.
Don't start with "um" or "okay."
Talk to your listeners as if you are having a conversation with them.
Make plenty of genuine eye-to-eye contact with members of the audience.
Avoid merely reading your presentation.
Focus on sharing your ideas. Communicate.
Use your voice expressively and meaningfully.
Minimize the uhs, ums, likes, and y'knows.
Enunciate words clearly. Don't mumble or garble them.
Speak with appropriate loudness and speed. Consider audience, place, and topic.
Use variations in speed, inflections, and force to enhance your meaning and hold audience attention. Avoid monotony.
Use your body expressively and meaningfully.
Look interested in your topic. Show your enthusiasm, sincerity, commitment.
Minimize distracting mannerisms and aimlessly shifting weight or moving about.
Use gesture and movement naturally to describe things, underscore transitions, and emphasize points.
Remember the 3 Es of Effective Delivery: Energy, Eye Contact, and Expression!