More windows on south than north, e.g., a salt box style house.
Space over windows to add overhangs to shade windows in summer, sized appropriately for latitude.
Simple pitched roof with few or no skylights.
Space for a ton of attic insulation.
Simple, rectangular shape, with long dimension running east/west.
If there are ducts, they should be within the conditioned envelope.
Air sealing is more important than insulation. Features that penetrate ceiling barriers, like can lights, will at least require some particular attention. If you insulate without air sealing, moist air can travel to cold places, and the resulting condensation can cause rot.
If you buy a house with siding that needs to be replaced, you can use it as an opportunity to add external rigid insulation, like foam board.
I live in FL and bought a north facing house. If I purchased a south facing house our AC bill would probably be 50% higher.
True, that doesn't apply so much in Florida, but when you have south-facing windows, you're supposed to have overhangs that shade the windows in summer and let in light in the winter, by taking into account the two different angles.
It's unfortunate that most builders don't know how to build efficiently. See the
Green Building Advisor site if you're interested in this stuff.