Debaters may have done extensive research and prepared powerful arguments, but an ineffective presentation can ruin days - or even weeks - of hard work, says Michael Chugani, veteran radio, television and newspaper journalist.
A good speech should be easy to understand, interesting and hold an audience's attention, according to Chugani.
'People's attention ... [can quickly] drift away,' he says. 'Speeches that drone on will make the audience switch off. You need to say things that are relevant to your audience. Speeches are meant to inspire ... the audience and you can [make them see] your viewpoint.'
Although a joke at the beginning or midway through a speech can break the tension, Chugani warns debaters to be wary of using this tool. A poorly delivered joke can work against them, he says.
'Say something that makes them [the audience] sit up and think,' he says.
'Adding lines such as 'you and I both know ...' can help listeners identify with the speaker - and you have to look them in the eye, even if you don't believe in what you're speaking about.'
Steve Schneider, an award-winning critic and columnist, says speakers should think about the image they want to convey.
'When you're speaking to younger people, smile a lot and look friendly and warm. When delivering a presentation to a group of distinguished colleagues, you still want to be accessible, but you must also maintain an authoritative air.'
One way to handle an audience, Schneider suggests, is to treat it like a single person.
'When there's only one person to worry about, you feel more of a personal connection to him. Your speech will take a backseat to the fact that you want the person who's listening to you to really understand what you're saying.'
Dr Agnes Lam Shun-ling, associate professor at the University of Hong Kong's department of linguistics, says a good speech should be tailored to an audience's expectations, and different groups expect different types of information.
For example, a speech at a scientific symposium should be given by an expert in the field, while public service announcements for the elderly should be easy to understand and remember.
She adds it's important not to cram too much information into a speech.
'If there is not enough time and you [try to] cram too much in ... you will be talking too fast and your points may not get through,' she says.
Lam also points out that body language and eye contact are important in conveying both the message and the speaker's confidence in what they are saying.
She says speakers should avoid reading from scripts and adopt a more interactive approach.
'The way people listen and ... absorb information from speakers is quite different from when they read. When people read, they have short-term memory constraints but they can backtrack. When you are listening, you cannot backtrack.'
Lam, who listened to American civil rights leader Martin Luther King Jr's speeches on YouTube on the night US President Barack Obama was elected, says the two are similar in their use of rhythm and repetition to emphasise important points.
'Many people will walk away from a speech with different viewpoints and takes on it, but if they all walk away with the central point, like King's 'I have a dream', that's good communication.'
All speeches are basically a form of persuasion in the end, she says, even if they assume a tone of objectivity and present evidence to back up the points.
Lastly, nothing makes a speech more appealing than a person who can deliver it confidently, without relying on cue cards. So, as Lam says, 'Practise, practise, practise'.