Diction
(level of formality through word choice)

Mark Twain said: "The difference between the right word and the nearly right word is the same as the difference between lightning and the lightening bug."

Aim for the "middle":

Low 
(slang/ colloquial/cliché)
Middle
High
(don't sound snobby or pretentious)
kids
children
progeny
freakout
scare
appall
right on
true or accurate
verity
give up
resign
abdicate/ forswear
chew the fat
talk
confer