How to Properly Focus a Landscape Shot
If you are using manual focus, simply choose the desired area of sharpest focus and leave it at that setting. If using auto focus, place the auto focus point in your viewfinder over the area of focus, press the shutter button half way to achieve focus, then turn off the auto focus. Now the shot can be recomposed as desired and the shutter button pressed without the camera refocusing on another part of the photo. A smaller aperture will give a greater depth of field as well, resulting in an overall sharper image.