Dialogue has to sound like real people talking. They may be outrageous people, and they may say outrageous things, but only the dullest people speak in cliches, and the dullest people are seldom worth writing or reading about. Another thing that real people don't do is pack their conversations full of plot information. Read your words aloud. Be prepared to be embarrassed, and if you're embarrassed because something sounds phony, you have some rewriting to do.
All writers rewrite.
If you're satisfied with your first draft, you're not an artist. That's not writing. As Capote quipped to Kerouac, that's just typing. You may break the rules. In fact, you should break the rules.