If you are buying a new car and have decided on a particular model. Go to the first dealership and ask for a price on that model.
Don't buy from that dealership and just get a card from them.

On the back of the card write a particular price which is reasonable and not over the top.
Example is... say the car you wont is 35 thousand dollars.
Write about 33,800 on the back of the card.

When you go to the next dealership you haggle for the price on the same model your after.
If they are within 400 or 500 hundred dollars of the price your written on the back of the other dealership card and they won't move on that price, you show them the card and say you were offered this price from this dealership.

Most of the time they will better that price by about a hundred or two below that figure.

By seeing the card with the price written on it they will most likely better that price so they get your business.
If they say no...just start walking out and say I'll do business with the first dealership.

Most of them will bend over for your business in today's market.

It's just a matter of being firm with your response on the price and set to walk if they don't agree with it.

It's quiet simple really.