Let's start at the beginning.
The foreground in landscape photography is like the opening paragraph in a good book. The foreground, like that opening paragraph, is where you're hooked. It's where your eyes first land, it's what first grabs your attention. The foreground element has you wanting to read, or more accurately in the case of a photograph, to see more, to look deeper into the frame.
Elements of compelling photos
Most good landscape photos have a foreground, midground and background that, when effectively included in the composition, will give the viewer a visual path to follow through the image. When done well, this "path" will have the viewer engaged with the photograph, looking into every inch of the frame rather than having their eyes get stuck at any one spot. It's my opinion that of these three elements, the foreground and background are the most important to creating a compelling landscape photo.
Establishing a visual path
One of the biggest benefits of including a strong foreground photography element is that it immediately grabs the viewers attention, giving them an obvious place to start their journey into your photo. If you're not one to be subtle, you can include a very prominent foreground, such as the weathered fence in the photo above. By composing the photo so that the fence starts right at the front left edge of the frame and then angles right toward the trees mid-frame, the trees then lead the eye toward the brilliant snow-covered headwall of Tuckerman Ravine.
This case shows the use of a foreground element that is equally as dominant as as the background. I chose to make it so dominant because of the way the human eye works. Being attracted to bright light, or in the case of a photograph, being drawn to the brightest object in the frame, I needed a foreground that was far from subtle. Otherwise, since the foreground area in this photo was still in the shade created by the surrounding mountains, a lesser foreground may have been missed entirely as the eye is drawn immediately to the bright, white snow.
The foreground can be nothing
Well not really nothing. How about nothing fancy?
When I was first getting interested in photography, I read a lot. One thing a lot of the articles talked about was the importance of including prominent foreground elements when composing a landscape photograph. I thought this meant I needed to include something truly awe inspiring. Something that rivaled the main subject for attention. Then it hit me.
The foreground really doesn't have to be much of anything, it needs to be a place to start along the visual path I mentioned before, and really not much more than that. The foreground can be as simple as the reflection on the surface of a pond. Or a single open clamshell on the sand.
The foreground can also be everything
Since I like to think of the "rules" of photography as mere suggestions, I'll often get creative with my foregrounds, sometimes making them the star of the image. I do this by setting my camera close to my chosen foreground so I can fill the frame with it. Then, rather than focusing about 1/3 into the frame to achieve the greatest depth of field, I'll focus closer to the foreground. This will render the background slightly soft and out of focus, though still readily identifiable.
A foreground element is the gateway into your image, using them well will help to create better landscape photos.