Within the past 20 years, companies have accumulated multitudes of data from their operations- data that gives them insight into process efficiencies, consumer preferences, product effectiveness, etc.   According to popular belief, this information is said to double every 18 months.  The problem here is not a lack of abundance, it is that the available data is not readily usable for strategic decision making.  It needs compiled, harvested and manipulated with the ability to be reported on in a minutes notice for a manager to make  an informed decision.  The question for many IT departments is, how do we do this? 

What are some techniques that you’ve used in the past that have enabled your company to build and maintain an effective data warehouse?  What are some obstacles we should avoid?