Aristotle's On Rhetoric describes the modes of persuasion thus:
Persuasion is clearly a sort of demonstration, since we are most fully persuaded when we consider a thing to have been demonstrated.
Of the modes of persuasion furnished by the spoken word there are three kinds. [...] Persuasion is achieved by the speaker's personal character when the speech is so spoken as to make us think him credible. [...] Secondly, persuasion may come through the hearers, when the speech stirs their emotions. [...] Thirdly, persuasion is effected through the speech itself when we have proved a truth or an apparent truth by means of the persuasive arguments suitable to the case in question.
Ethos (plural: ethe) is an appeal to the authority or honesty of the speaker. It is how well the speaker convinces the audience that he or she is qualified to speak on the particular subject. It can be done in many ways:
By being a notable figure in the field in question, such as a college professor or an executive of a company whose business is that of the subject.
By having a vested interest in a matter, such as the person being related to the subject in question.
By using impressive logos that shows to the audience that the speaker is knowledgeable on the topic.
By appealing to a person's ethics or character.
Pathos (plural: patha or pathea) is an appeal to the audience’s emotions. It can be in the form of metaphor, simile, a passionate delivery, or even a simple claim that a matter is unjust. Pathos can be particularly powerful if used well, but most speeches do not solely rely on pathos. Pathos is most effective when the author connects with an underlying value of the reader.
In addition, the speaker may use pathos to appeal to fear, in order to sway the audience.
Logos (plural: logoi) is logical appeal or the simulation of it, and the term logic is derived from it. It is normally used to describe facts and figures that support the speaker's topic. Having a logos appeal also enhances ethos (see above) because information makes the speaker look knowledgeable and prepared to his or her audience. However, data can be confusing and thus confuse the audience. Logos can also be misleading or inaccurate.