When photographing an image with some type of line, path, or object that will go out of my frame, my very first instinct is to find a way to push it towards one of the corners. This also works well for items that are coming into the frame, too. Compositionally speaking, this type of framing is very pleasing. It can prevent a road, stairway, or limb from the appearance of being chopped off or awkwardly positioned in the photograph. It can help bring balance to the image as a whole.
Keep in mind that to do this, you may need to tilt your camera. Don’t be afraid! Not all images need to be straight up-and-down. 🙂
Here are a few more examples of using the corners of the frame to balance the composition of a photograph: