Simple. Ask these two questions:
Is now a good time to sell?
Is now a good time to buy?
If they answer yes to either of those questions and you’re in the United States of America, walk away.
If a realtor says, “The party line is that it’s always a good time to buy, but honestly, I’d wait a year” take that person’s business card and don’t lose it.
See the about page for more. 
