Article in English: If you want to have stellar presentation skills, then you have to sound like an expert on the subject you're speaking about, whether it's the mating pattern of sea otters or the inexplicable popularity of Miley Cyrus. Though having a degree or lots of experience in the field can help convince your audience, researching the topic as thoroughly as you can is your best bet for making them believe every single word you say.   Hit the Internet and library and talk to experts to get a better idea of your subject, until you feel that you can effectively give a presentation on your subject and answer any questions that will arise along the way.      The more research you do, the more confident you'll be about giving your presentation. And if you're more confident, you'll be better at giving your presentation. If you want to polish your presentation skills, then you have to give a lot of thought to who will be in the audience. If you know you'll be presenting to your fellow classmates, then you have to think about what will intrigue and interest them. If you're presenting your topic to a group of specialists, then you can assume they know the lingo; if you're presenting a complicated topic to a group of eighth graders, however, then you'll have to simplify it so they can follow along. Though you can't know everything your audience will and will not want to know, you can figure out a lot based on the age and the make-up of the group of people you'll be presenting to. Keep this in mind as you hone your presentation. Chances are that you have a certain time limit for giving your presentation, whether it's half an hour for a work presentation or ten minutes for a presentation in class. Whatever your time limit is, you should make your presentation so it fits comfortably under the time limit so you don't spend your time talking too fast to try to hit every point; however, you shouldn't make it so much shorter that you're left with a lot of "dead time" at the end.  The closer your presentation is to meeting that time limit,...

Summary in Chinese:
研究你的话题。 了解你的观众群。 根据演讲时间长度，决定内容。 演讲时添加些多媒体因素。 演讲的思路框架要清晰。 练习，练习，再练习。