Practice is paramount, more on that later, but what else really matters:

  1. Body language (addressed previously) http://in.test/wp-admin/post.php?post=476&action=edit
  2. Practice pauses, silence is golden (FAR better than filler words)
  3. Avoid fillers – Um, Am, Well i suppose, Like (if you are from Cork, Ireland) – These were all my fillers before i eradicated them!
  4. Don’t fidget, place feet firmly on the ground, keep your hands still.
  5. The pace of your speech is crucial (nerves = speed).

All of the above can be tested by speaking in front of a mirror and recording videos of yourself answering questions

In most cases, people are not aware of the negative impression the above points can create, work on these and you will be streets ahead of the average candidate.