Here are a few ways I found by interviewing multiple people (Credits next to methods)
1) Use your imagination (Dennis Chan)
(Trust me. Really works)
This method is called Mental Imaging, or mental picture. It's a representation in a person's mind of the physical world outside of someone or something. In another words, day dreaming.
If the audience isn't too close to you, you can imagine their heads as anything your mind can create.
For example: Imagining any heads as fruits seen from a distance critically brings down your stress level based on the theory: Mental Imaging
2) Chewing Gum (Terence Wong)
It has been scientifically proven that chewing gum decreases the level of anxiety of a person, in one study, participants who chewed gum twice a day for fourteen days rated their anxiety as significantly less than the non-chewers.
The mind prevents a person from eating anything under a stressful condition, but since you're chewing gum, you're mind is in a collision course with the gum. Making you nervous but at the same time relaxed.
Like if your teacher ever complains about that gum issue, use this excuse, it guarantees victory but with the cost of detention.
3) Script it / Memorisation <Works a day before "execution"> (Parents)
(If your plan is written in java format, good luck for the presentation)
This technique is called Memorisation as mentioned above. After effectively planning on your steps on what to present, you must spend the time to actually read it for at least 10 minutes, it has been scientifically proven that when a person goes over somethings, the brain is most likely able to remember at least 60% of work that you did. It may not be a lot but it's still better than doing nothing pretending that something will work.
4) No self doubting ( My Græt Grand parents )
(Please do NOT underestimate the potential of wastes)
As they say, believe in yourself for each and every one of us have a potential to change things.
Most of the times during presentation, people tend to doubt their ability to make it through or even speak up which eventually led to an embarrassing failure. Please, don't doubt yourself.