You could use rather in a situation where you are saying you would have done something else. For example: "I would rather travel in a car than in a plane". "Rather than doing the homework, I would watch TV."

Another usage of rather can be: She is rather pretty, don't you think? Rather can be used as an adverb as well like in the above example. In this case you are using 'rather' in the same way people use 'quite' or 'fairly'. The common usage of rather is (like the above poster showed): I rather get an A on my test than a B. - In this situation, two things are compared (A and B). And rather is used as an adverb meaning they would prefer an A versus a B.

You can use "rather" in situations like, "Would you rather have pizza or chicken for lunch?" most commonly used in questions when asking for a choice.