Designed and built an EDW from the ground up, including hourly CDC from one of the largest ERP applications. EDW is updated hourly serving both analytical and batch data integration operational needs.
Kept data staging a separate project from the actual EDW so business didn't confuse expectations from different stages of delivery.
Purchased and implemented customer matching tool early in the project.
Not started the project until I could hire qualified staff - don't assume you can find and acquire good consultants as part of the project schedule. Finding and testing qualifications of consultants absorbed months of effort and wasted time. In retrospect, I would have paid 3x as much and hired someone great to get it done fast and effectively rather than multiple inadequate staff at cheaper prices who require micro management.
Got written commitment to support project by IT and business staff for periods of time needed.
Agreement by executives up front on prioritization against other projects.
Agreement as to prioritization and balancing cost verses time.