The short answer
Bring room and furniture measurements, your list of favorite homes, and any information you already have about your land.
Bring your questions too
Ask what is standard, what is optional, which plant builds the home, what the display model includes, and what the complete project may require. Photos and notes on your phone are useful while you compare homes.
Use your everyday needs as a checklist
Measure furniture you plan to keep, especially beds, sofas, dining tables, and large appliances. Include room to walk around them and open doors. A room can look spacious when staged with furniture that is smaller than yours.
Take notes on each model instead of relying on memory after several tours. Compare storage, laundry access, kitchen work space, and bedroom privacy. You can start a useful tour without already having every financing or land question settled.