Commonly confused words

Affect is usually the verb and effect the noun: the weather affects my mood, it had a strong effect. Lose is the verb, loose the adjective: don't lose your keys, a loose shirt.

Principle is a rule or belief, principal means main, or the head of a school. Complement completes something, compliment is praise. Stationary means not moving, stationery is paper and pens.

Fewer goes with countable nouns, less with uncountable ones: fewer cars, less traffic. Among is for three or more, between usually for two.