Change is constant and most IT organisations and IT service providers have adapted to a formalized methodology to manage the related work. Change is important because it enables the businesses to respond and meet the ever-changing needs of customers. This thesis describes the most used methodologies for managing work related to change and their benefits and practical implementation. However, a formalised methodology is not like a ready-made set an organisation can just start using, but more like a guideline which the organisation needs to tailor to suit their need. Processes and culture need to support the methodology to be successful. Co-existence of multiple different supporting methodologies is often required to achieve the best results. A literature review is used to collect data for this thesis, which then describes commonly used Project Management, Agile methodologies, and IT Service Management practices. A traditional Project Management (waterfall) approach divides the activities into a sequence of separately executed steps. It focuses on preparatory planning where factors like budget, scope, and schedule are prominent and change to original plan is not desired. Agile prioritize quick and flexible adaptation to changes, iterative development cycles, collaboration, and commitment to continuous improvement. Both have their benefits and drawbacks. Some organisations and their Project and Service Management characteristics are described in this thesis. Recommendations and guidelines are provided to avoid the most common pitfalls and how to aid in delivering successful projects. Some of the tools that are commonly used to support organisations are described. Many organisations are well on the way to leveraging the methodologies described in this thesis, but some are facing serious challenges. In general, inefficiency in management can have detrimental effects on the organisation's success and losing the competitive advantage. A key finding is that the focus needs to be in providing business value and consistent execution of the selected methodology. Project and Service management in general are broad topic but it is possible to piece together the big picture and define the place of each methodology and formulate recommendations and guidelines for implementation. However, each environment is unique and thus requires processing according to its features. Knowledge of all the intricacies related to Project and Service Management requires years, if not decades, of experience. This work is no substitute for that experience but understanding the key points is vital for success for organisations and their employees.