Checking Edmunds.com for the car's True Market Value would help. Furthermore it can give you a good idea of what people in your area are paying (in general) for the same car.
Kelley Blue Book tells you what dealers are asking for. Edmunds tells you more or less what it actually sells for. NADA prices give you another estimate of what the car is worth.
I say calculate the Edmunds TMV, balancing it out for your location, the color, options and mileage. Once you have that number, you have a better idea of what the car is really worth. Offer what you feel comfortable paying with. Don't care about looking like an idiot because it's money coming out of your pocket, not the dealership's. Sometimes, if you're not afraid of walking away if the dealership doesn't give you the deal you want, then yes, you can get them to drop their price.
One mistake is to let impatience take over. If you can't be a little patient, then you'll probably end up overpaying for the car (which will only hurt in the long run).
But one thing: If you're going to have to sell the car in a year, then why bother buying it...? I mean, would it be worth it?