I'm assuming you are referring to formal 'debating' Debating and so will base my advice on that fact. Keep in mind I've had no formal training, apart from partaking in the practice myself. Nevertheless, I feel that I can give a well-rounded appraisal.
1. Eye-Contact: Frequent and direct eye-contact is absolutely essential in hammering your point home. By frequent eye-contact, I mean a few times every sentence; try to make sparing use of written prompts, using palm cards only as a guide. When I say direct, I mean look those adjudicators right in the eyes. I've noticed a lot of people have little trouble looking up from their cards, but only a select minority actually stare down the adjudicators. Ultimately, this helps portray you as a woman brimming with fire and passion who can effectively convey strong ideas. Always remember, an effectively-delivered and presented speech can often defeat a more solid and well-structured argument.
If you're someone who gets particularly embarrassed when speaking, I recommend practising your eye-contact in front of a mirror to start with before progressing to actual people; for some, it makes all the difference.
2. Strong Voice: A strong voice is critical in conveying your conviction and is in my opinion, the single-most important aspect of any debate. Always take steps to ensure that you project your voice, varying your tone, pitch and inflection where appropriate. Of course, you don't want to be screaming but ensure that you remain forceful in your delivery. Pause often for emphasis as this helps create a tone of solemnity or importance.
All too often I've seen people debate like it's the Sunday Country Club with a forced smile and gentlemanly demeanor. Don't get me wrong, this can work for some depending on the subject matter. However, I guarantee a stronger, more evocative speech is far likelier to leave a lasting impression than a speech that while well-polished, was delivered mediocrely.
3. Gestures: Again, try not to overdo it, but well-chosen gestures, whether they be pointing, fists or simply placing your hand on your heart can go a long way in demonstrating your conviction. This is essential in any debate.
4. Humour: Witty or sarcastic humour is a great way to keep your speech front and centre in the minds of your audience, especially the adjudicator. Remember, this is not an essay; humour is a great way to create some levity.
5. Facts: You should always endeavour to include relevant facts, statistics or references to contemporary events. This is why it's often so important to have a good connection with the happenings out in the world, you never know when it might come in handy!
6. Address the Question: Always address the question in its entirety, defining each individual word of importance as it comports with your case. Usually it's the smallest of words or phrases that can determine the course of debates. Try to look at the variety of different angles you can tackle the question and always attempt to anticipate the kind of arguments your opposition will levy. This well help make your case more prepared and thorough.
7. Rebut Your Opponents: Take care to always address the claims of your opponents; don't let them fester! I know it can be hectic, but try to rebut every point while simultaneously reaffirming the primacy of your arguments. However, never introduce new arguments while rebutting as this is held in low-esteem by adjudicators and derided as poor structuring.
Hope I've helped!