Landscape, Seascape or Cityscape, they are all scapes to me. There are so may guidelines about landscape photography; the rule of thirds, leading lines, balance, etc.; and if you are interested you should follow Gavin Hardcastle on fototripper. I have not been paid to say that; he doesn't know me; but I follow him myself. Landscape photographers will spend hours at a scene, composing the image and then waiting for the right light or cloud to come along.
I am not a landscape photographer. Most of my images have been taken whilst I have been walking with friends and I do not have the luxury of time. That is not to say that I do not think about composition. I always shoot more of the scene than I need so that I can recompose later with a subtle crop. (maybe not so subtle).