stack it all up and ask yourself "If these were the same price, which one would I choose and why?"
Typically, you can understand pretty fast why, what, and where the difference in values exist.
Location, Elevation, Views, quality neighboring homes, convenience, drive-time, sewer/septic/street lighting, etc, etc, etc.
Usually, it goes far beyond that, to conditions that you won't understand until you live there and discover why turn over is higher and desire is lower. For example, there could be more water run-off zones and water retention areas as you get lower in elevation, therefore mesquitos may be more predominate in a particular area.
Market Values are determined based on what buyers are willing to pay. Only at an extensive, close-up look can you really determine why an area sells for less.
Do you drive past trailers? Do the curbed streets end? Are the street lights not as plentiful? Sidewalks? Trees? (this goes for any area, just to give an idea)
If you are considering purchasing a home, I encourage you not to overlook the value of hiring a great Real Estate Agent, because what seems unknown to you, is the obvious to a professionals - it just cost you a lot more to discover it. know what I mean?