Kennings and Homeric epithets

An Anglo-Saxon kenning is a descriptive pfrase which replaces the noun: 

The ship sailed over the whale-road.

A Homeric epithet is an adjectival phrase which adds to the noun:

The ship sailed over the wine-dark sea. It usually has two words: bright-eyed; rosy fingered.

Two words you must not use in a literary essay.

 Upset and incredibly are inappropriate in formal writing. Upset is too colloquial and bland and incredibly means the opposite of what it says. 

Verbal, oral and aural

Strictly, verbal means "in words" and refers to something written whereas oral means spoken. Aural refers to the sense of hearing.

Practical Criticism

This is a method of approaching a text, often a poem, where the reader or student is given no background information about authorship, date or background. The analysis must therefore concentrate on the words on the page and devices used. It has fallen out of fashion recently since its promotion by I. A. Richards in the 1920's but it can be a useful method of ensuring a fresh response to a work.

Tautology and pleonasm

These two terms are similar in meaning as both refer to unnecessary words. Some critics regard them as interchangeable but there is a useful difference.

Tautology refers to the repetition of words with the same meaning: big, huge, large man
Pleonasm occurs when the idea contained in one word is repeated by another: huge giant.
Pleonasm could be seen as a sub-type of tautology. The adjectives are: tautologous and pleonastic
Repetition can be used effectively for emphasis.

Principal and principle

These two words sound alike and so it is only in writing that their endings are confused.
Principal means head or chief and you can see the a in both. You could also think that the Principal of your school will never be your pal.
Principle means a belief and a way of remembering it is to think of asking someone to follow it please where you can see the ple in both.

Affect and effect

These two words are easily confused. In practice you can forget about affect as a noun (the affect) as its usage is largely psychological/medical. This leaves:
affect as a verb meaning "to change": the experience affected his attitude
effect as a verb meaning "to bring about":  she effected an improvement in working conditions
effect as a noun meaning "result": the effect was just what she wanted