In addition to the points mentioned above, from my experience a very critical step in the project initiation phase is to lock down the scope of the project. In my company I believe that one of our biggest struggles is scope creep. We just proceed with a project with a general idea of what is going to be in scope of the project, and often allow the scope to be increased later on in the project without doing a complete assessment of the impact on the project, leading to project delays. Therefore, I believe that locking down the scope as early as possible is very important. I understand that there may be a need to expand the scope at a later point. However, there should be a rigorous process to assess the impact to the business case and compare that to the impact to the project if you keep the scope the same or change the scope, and then make an informed decision based on this assessment.