When designing and building a new house, it is important to understand how the location and orientation of your home will affect your home's energy profile. Houses oriented longitudinally require less energy for both heating and cooling, resulting in lower utility bills and increased comfort.
How the Sun Affects Building Design
The Earth is positioned on an axis that causes the Sun's position in the sky to change with the seasons. This is apparent in the summer when the Sun is further north in the sky than it is in the winter, when the Sun tends to be lower in the southern sky. This relative position change of the Sun is a major heating and cooling factor that must be considered to maximize or minimize a building’s passive solar gains in different seasons. Houses oriented towards the sun can save between 10-40% on home heating.1
Image source: www.nachi.org
Typical Design Practices
Orient your home longitudinally.
This means that the length of your home should be oriented east-west, and the smaller width of the home should be north-south. This will maximize your solar gains from the south during colder months, and minimize heat losses due to wind on the eastern and western sides.
Find the true South.
Notice that the solar north-south is different from magnetic north-south. The short axis of your home should orient toward solar north-south. 
Orient your floor plan towards the Sun.
By designing your home with frequently used rooms, such as the kitchen and living room, on the southern side you may appreciate the sunrays in the winter, and will also be relieved from the sun on warm summer days. Patios and decks can also be built with this in mind by placing them on the southern side so they receive more direct sunlight, giving you more time to use them. Areas that are less frequently used, such as the laundry room and garage, should be situated on the northern side of the house, as they will act as a buffer against cold winter winds and will not require the natural lighting benefits that you may want in your living spaces. 
Plant trees for shading.
Trees are important to provide shade in the warm summer months, but can also starve the house of natural light. Deciduous trees should be planted on the east and south sides of your home. Their canopy can provide solar shading in summer months while in winter months,they lose their leaves to allow natural light and solar heating of the house. Evergreens should be planted on the north and west sides of the house to provide shade in the hot summer and serve as a wind break in the cold winter. 
Install windows on your south-facing wall.
These windows will serve as a heat source in the winter months. You can learn more about this technique on the passive solar page. 
Of course, all of these strategies may not always be possible. There are other aspects of a building's orientation such as street appeal, scenic views, and drainage considerations that may factor in when considering your home's orientation. Straying from the strategies outlined above can have a minimal energy impact if you stay within 30 degrees of east-west. It is recommended that you contact a building inspector to maximize these benefits based on your location.
Resources
- "Building Orientation for Optimum Energy" by National Association of Certified Home Inspectors - An article discussing orientation of a home in great detail.
- InspectorSeek - Helps you find InterNACHI certified inspectors in your area.
- Wind Rose Diagram - A valuable tool to determine the orientation of your building in order to utilize the natural wind cycles.
- Building Information Modeling, Massing Tool - A valuable tool in the pre-conceptualization stages of building for determining the best shape and size of your home based on the natural conditions outside. These tools generally cost money, but you may contact a local architect if you would like to model your home using their software.
- eQuest - Link to an example energy simulation tool provided by Department of Energy