ICT energy efficiency is a growing concern. A great effort was already done making hardware more energy efficient and aware. Although a part of that effort is devoted to specific software areas like embedded/mobile systems, much remains to be done at the software level, especially for applications deployed in the Cloud. There is a increasing need to help Cloud application developers to learn to reason about how much energy is consumed by their applications on the server-side. This paper presents a set of tools which guides the developers of Cloud applications in key steps. First, at requirements stage, in order to capture energy goals in a measurable way and relate them with important Non-Functional Requirements (NFR). Second, at design level, an UML profile supporting energy Key Performance Indicators (KPI) is used in order to keep tracking off those goals and metrics across the functional design of the application. Third, at runtime, measurements probes are automatically deployed and the collected data is processed in order to be analysed at the previously goal level. Specific tools for analysing the energy behaviour and helping in making a choice among different design alternatives are also proposed.