There are certain fundamentals that need to be in place to increase the probability of project success. The first of these is to have an active and committed Business Sponsor. The primary roles of the Business Sponsor are to provide funding, help clear obstacles to success, provide resources and make key decisions.
It is surprising how many projects (IT projects especially) proceed without this key building block. The thinking is that the merit of the project itself will drive it to successful conclusion. This is a huge mistake. Projects like this will typically encounter a lack of cooperation from the business units as their priorities do not match the priorities of those driving the project. It is ok for IT to get the ball rolling, but before the project is officially approved, the Business Sponsor must be identified and take ownership.