Supply and demand biggest factors for real estate investments

First, the market is more important than the property.

Second, value is drived by supply and demand.
Third, you should invest when supply = high and demand = low
 Forth,  The 3 drivers of supply and demand are:

1. Location (visibility, rare qty,...)
2. Employment 
3. Population

Recap:

When you are in a context of  supply = high and demand = low in a region, buy real estate at great location if population and employment should grow.