Not only the application, but already the selection of a method requires competence and experience. It is important to identify the individual right method, out of a variety of different ones, or to create a new methodological approach. The decisive factors are the particular problem, its temporal occurrence and the available resources.
Which system is considered and where are its boundaries?
How do you describe the problem completely?
What are the results of the applied methods?
What actions are necessary for reaching the aim?