Do you go where everyone else goes?

When you’re planning on marketing to a specific audience — do you go where everyone else goes?  In other words, if all your competitors advertise in a specific trade pub or in Times Square, do you go there too?  Or do you think it’s smarter to find a quieter street corner?

If you decide to go where all the noise is — how do you make sure you get heard? 

If you decide to go to the quieter street corner, how do you make sure the audience knows you’re even there?