Nowadays, due to a large number of changes in the external environment, as well as increased competition, organizations must actively support business processes. Internal management processes must be constantly improved. To understand whether a company is developing in the right direction, it is necessary to conduct a maturity assessment. The directions of changes in enterprises should be well designed and based on analysis of the gap between the present and expected state definition. The diagnosis for the present state definition should be holistic, reliable and for the expected state-based strategy and goal recognition. Hence, the goal of the paper is to present the methodology of a company’s self-assessment and definition of an individualized improvement strategy to strengthen the company’s ability to thrive and prosper. The paper includes a presentation of the diagnosis methodology based on maturity models and the resilience concept and its validation based on experts’ opinions and a case study. Companies need a diagnosis to know where they are, and guidance to move in the right direction, which makes the results of the research utilitarian. The methodology can be used for self-assessment, benchmarking and designing an improvement strategy.