Visualization is the process by and through which everything comes into being in our lives, both good and bad. Visualization is in our nature; it's simply a quality that all human beings possess. We are doing it all the time.
Therefore, we need not worry about the mechanics of visualization. They operate automatically. The more salient concern is the service to which this wonderful, creative faculty that we possess is put. On this question there are two options. We can either use this tool in service to our own egos or in service to The Good (see The Philosophy of Success for a discussion of this assumption).