Every manager should follow certain principles in order for his work to be effective, that is, he should set clear goals and how to achieve them. He should also pay attention to prevention - to prevent shortcomings rather than to solve problems that could have been avoided. It is also important to set priorities, timely and plan the progress of tasks, and so on. The manager's interest should not only focus on the company and its operation, but should also focus on the customer and his satisfaction.