Whenever I show an international visitor around, I try to shy away from phrases like, well, "to shy away from" since I realize that they're not the most common phrases to learn when picking up a language. I also try to avoid saying things like "picking up" when I could say "learning" and try to avoid--for simplicity's sake--interrupting my sentences with extra clauses or asides.
But most of all, I try to avoid idioms. I liked today's Left Handed Toon about "Kick the Bucket" and other language's similar idioms. Click the comic below to be taken to the larger version.