Never underestimate the value of early stakeholder engagement to a project.
Not engaging the right stakeholders early enough in your project creates added headaches and problems with project delivery.
Never underestimate the value of Senior Management involvement in your project!
Your ability to gain buy-in and support from across an organisation is really dependent on having one or more Senior Managers along for the ride. Your project needs to be something that these managers talk about, whenever the opportunity arises.