Companies in different domains profit from data. However, in order to benefit from a large amount of scattered, unstructured data, they must be collected from multiple sources, structured, cleaned, stored in one place, and properly visualized. In order to create an effective BI (Businesses intelligence) solution and access the mass of necessary data, use the benefits of transferring software software to a competent team of experienced and qualified BI programmers and data engineers. Business Intelligence (BI) systems are today considered the main strategic tool of many well-established companies such as well-known ones such as: Lufthansa, TDC Telecom and AT&T. Of course, the knowledge gained from the experience of these companies could be a useful guide in building efficient BI systems. Therefore, this professional paper lists the main points arising from the experiences of the world practice of building successful BI systems. Business intelligence systems are expected to accelerate the II decision-making process while maintaining the quality of each decision, improving their product development cycle, maximizing profits from existing product lines and discovering new opportunities, establishing better marketing with robust CRM. However, more than 50% of BI projects do not meet these requirements. This final paper explores and suggests thorough solutions from known BI practices.