The first thing you have to do is forget any auto-exposure mode. Otherwise, your shots will come out overexposed. Digitally, go to manual mode and bracket your exposures by shutter speed, keeping the same aperture. With film cameras, do the same, but you will want to overexpose for b&w, because you are trying to capture shadow detail.
You will also want to use a tripod or monopod, because your shutter speeds will be slower - and if you are doing landscapes, a tripod really is a necessity, anyway...so use one!
This photo was shot at 1/6 sec at f8 with my FujiFinePix S7000, on a tripod. No manipulations were performed at all after downloading the image.