The first time I learned about ITIL when I was working in Etihad Airways. It gives you a complete guidelines on how to manage IT services. The concepts are not limited to IT but it can be used in every industry. Service is everywhere and managing it requires a level of expertise. Everyone does the job in his/her own way but it there is a certain language and process that is followed life becomes easier.
ITIL stands for Information Technology Infrastructure Library. It is actually a set of books or publications. Whether you are developing a small hello world or building a high end community website or an app, you certainly have in mind to provide some kind of service. You begin by setting up a Service Strategy. It is the foundation of any IT service. You develop a vision and a mission of the service. You look it from all aspects strategically and financially. You look at the competitors out there. You Plan Do and Check. Every big project starts with some kind of inspiration and strategies. In the Service Strategy stage you set the layouts of the service.
After Service Strategy has been completed, you move on to Service Design, Service Transition, Service Operation and Continual Service Imrovement.