According to Project Management Institute "a project is a temporary endeavor undertaken to create a unique product or service." Patel and Morris have stated, "The life cycle is the only thing that uniquely distinguishes projects from non-projects." 
The Project Manager requires various general management skills during the different phases of the project.
Initiation and Scope Definition, comprises determination and negotiation of requirements, feasibility analysis, and process for the review and revision of requirements. Planning follows and includes process planning, determining deliverables, effort, schedule and cost estimation, resource allocation, risk management, quality management, and plan management.
The project manager's role is to verify the requirements, bring in the experts and revalidate requirements and technical feasibility. He needs to baseline the requirements, cost, schedule, and quality of delivery to the smallest detail, thus setting up a solid framework to start work on the project. This phase is critical because unless requirements are set and baselines are defined, the project cannot take off.
The project manager needs negotiating skills, estimation and scheduling skills as well as, team building capabilities that help set the base for delivering a project of required quality at a realistic budget.
In the Development phase, implementation of plans, supplier contract management, implementation of measurement process, monitor process, control process, and reporting and the various tasks in an IT project.
It should be noted that although project objectives have been defined, there may surface problems when the actual developments are taking place. ...