The best way to learn proper English is to read news report, and watch news on TV. Watching TV shows is a great way to learn casual English, slang words, understand culture reference and humor. If you have already watched these shows then you may recall the words used in the following dialogs.

Pretty good.
Can't complain.
The Big Bang Theory Season 5, Episode 20

That part was PRETTY good.
The Big Bang Theory Season 8, Episode 19

[NANCY SINATRA'S "IT'S SUCH
A PRETTY WORLD TODAY"
PLAYING OVER SPEAKERS]
Breaking Bad Season 2, Episode 4

If you're not gonna learn how to do this,
they make some PRETTY good clip-ons.
The Big Bang Theory Season 8, Episode 8

It is PRETTY spicy.
The Big Bang Theory Season 4, Episode 18