In most cases a competitor is not doing exactly what you want to do. If your idea involves some sort of a gimmick or very specific point of attraction and that

In most cases a competitor is not doing exactly what you want to do. If your idea involves some sort of a gimmick or very specific point of attraction and that is already being used by a competitor, then sure, maybe you should pick a different idea. But otherwise there is likely much room for competitive advantage.