Talk about each and every room in the house, the basement, the garage, and the exterior. Also talk about each of the options you selected, and look at the blueprints - ask them to tell you how to read the basic things on them at the meeting if you need help. The buillder builds off the blueprints, so look at them - a lot of questions get answered there.
In each space, make sure you know what finishes are going to be installed and what they look like. Keep asking - what does that look like? They should be able to show you an example in the model, or in a book, or on another house. You saw the flooring when you did your selections. Pay attention to location also. For example...
Flooring - Color/Type - Where are the flooring breaks between rooms?
Cabinets - Color/Type/Upgrade?/Drawers? Doors? Height? Knobs/Handles? Locations?
Faucets - Color/Type/ Picture? Locations?
Sink - Size/Color/Type/ Picture?
Countertops - Color/Type/Backsplash?
Toilets - type/size
Vanitys - type/size/location
Pedestal Sink - type/size/location
Windows? - Location/size/type
Exterior and Interior Doors - Location/size/type
Door Knobs - type/deadbolt?
Lighting fixtures- type/location/picture
Light switches/plugs - type (location is normally set for you - if you have special requests, let them know)
Cable outlets - location/number?
Phone outlets - location/number
Closet/pantry shelving - type/location?
Trim - what trim is used in house? locations? Crown Molding?/Chair rail?
Bathtubs/showers - type/size Tile or Fibergalss finish? Color?
Shower doors - type/location
Rails - type/color/see picture
Hardware - Toilet paper and towel rods - location/type
Fireplace - location?surround?mantle?
Heating vent covers - location?type?
Appliances - see pictures of these. color? What appliances do you get?
In the basement, in addition to any of the above that apply...
Heating system? Location - Fuel? Service? Warranty? 1 Zone or Two?
Hot Water Heater - Location - Fuel? Service? Warranty
Location of Columns and anything else which will impede future finishing. Columns can't be moved.
Basement Bath rough in? Type/Location?
Basement Exit? What type of door?
Electric panel location/finish?
Grading - how will the finished contours of the lot look? It will look different than now in some cases.
Seeding/sod? What is warranty? Will they seed in winter? What if it doesn't grow?
Siding -- type/size/color
shutters - type size/color/locatoin
Brick/Stone - type/size/color/location
What will need maintenance on exterior? What is painted?
Exterior Trim - Color/location
Window/door features (fancy trim pieces over windows/doors) - size/location/color
Shingles - type/color/see sample
What is off of back door? Deck? Covered with rail?
Driveway - width? will they do 2 coats?
Water/Sewer connections - location
porch - size? location?
Steps to front porch?
Steps into house from garage?
Hose bibb location/number?
Exterior electric outlets location/number?
Location of outdoor AC unit? Heat pump?
Location of water meter? gas meter?
Drywalled? Full or partial?
Garage door opener?
Garage door type/size/insulated? Windows?