Price per square foot really varies by what type of home you are looking for.
Is the type of architecture something that local builders have experience with? Are the materials used similar? For instance, Texas has a lot of full brick homes, while the Southeast has a lot more vinyl or hardiboard homes. Are you looking for a one or two story home? A one story is more expensive per square foot, because more foundation and roof are needed, which are major contributors to the cost of the home. Are you looking for a very large kitchen with granite countertops, or a more typical 10x10 kitchen with a nice Formica countertop? There can be a large variance in finishes - tile vs. vinyl in bathrooms, two-piece crown molding vs no crown molding, etc.
Also, by square foot cost, are you including the cost of land, or are you planning to purchase a piece of land? If so, find out whether the builder is including septic/well or city water/sewer hookups, permits, and land clearing/preparation in the cost per square foot.
Hope this helps as you start your search!