Over the years, numerous studies have looked at why projects fail.
Most of these studies conclude that common sense factors (better project management, communication, stakeholder involvement and change controls) would have reduced failure rates.
However, more recent research suggests that while best practices and better tools do indeed help - there is nothing more important than choosing the best qualified people to run the project.
Having the right people on the team makes everything easier. Great team members already understand the core competencies of project management - they know what needs to get done, and they are laser-focused on accomplishing the project's goal(s).
BOTTOMLINE: One of the most important assets an organization has - is its leadership. Without strong leadership to make the right decisions, it doesn't matter who you have working on projects, nor does it matter what best-practices and project management tools you use. Incompetent leaders can lead the best project teams, the best technologies and the best organizations with the most resources - into an abyss of total project failure.
#1. Leadership....#2. Project Teams....#3. Best-Practices and Technologies - in that order.