How do I reverse the draft on my chimney when smoke is coming into the house?

I have a wood-burning fireplace, and most of the time the smoke does what its supposed to do and heads right up the chimney. But how do I reverse the draft when I light a fire and all the smoke comes pouring out into the living room? I rent a townhouse and I'm not going to invest any money in a place I don't own, so one of those chimney cap things isn't really an option. Thanks for any help you can give me!