By a good background of knowledge and by a sufficent preparation, anyone can give an effective oral presentation. This article has been compiled in hopes of providing some helpful instructions on effective ways to present scientific communication. It is aimed at improving the quality of presentation and is designed primarily for young scientists who might be approaching their first professional conference, but other colleagues might also find useful information for improving their own presentations. Effectiveness of an oral presentation depends on the ability of the speaker to communicate with the audience. An important part of this kind of a scientific presentation is focusing on two to three key points and emphasizing those points during the talk. It s observed that the audience learns best when the information presented matches their needs; when they are motivated to learn and anticipate that they will benefit from the experience; when both visual and auditory aids are used; when the aims of an oral presentation are clear, relevant, and in context; when they are actively involved in the learning process or when the experience is enjoyable. If our instructions are kept in mind during both preparation and talk of an oral presentation, the people will be attentive and speaker s effort will be effective. Many oral presentations concern interesting scientific work, but are nevertheless difficult to follow because the speaker unknowingly makes a number of presentation errors. By far the largest mistake is that a speaker does not realize how an audience listens. If we are well aware of what errors we should avoid, the chances are high that we shall be able to greatly improve our oral presentations. These possible errors are evoked in this article.