Aristotle describes three persuasive appeals:

1. Ethos. How you convince and audience of your credibility.
2. Logos is logic and reason using rhetorical devices such as analogies, examples, and citations of research. Structure and content are also important.
3. Pathos is neither good nor bad but may be irrational and unpredictable, such as advertising. For example, beauty products promise to lessen our physical insecurities; Cars make us feel powerful.

Knowing which rhetorical appeal to use depends on your audience and purpose.