Look around and find the floor plan you want, and the models you want. Most floor plans are offered as numerous makes/models. Search the web for pricing and come up with the price you are willing to pay. Then email numerous dealers and let them know what model you want and the price you are willing to pay. Let them know you are ready to buy now. If it's a reasonable offer they will take it.
or my favorite is to go in with the check made out and hand it to them. If the hesitate, start to tear the check. It's kinda fun :)