Some images do not need much foreground interest. A beach scene with a beautiful lit dramatic sky typically does not rely on a foreground to make the image. Other images just have to have a strong foreground or they break down. A strong foreground gives you depth. It anchors the viewer's eyes. Hopefully, the background will then draw the viewer into the image. However, without a strong foreground element the viewer eyes will move into your image (if there is something interesting there) once and then move on to the next image. I want viewers to look at my images for as long as possible. A strong foreground element also serves the purpose of pulling the viewer's eyes back from the background to the starting position of the foreground element. Thus the viewer will repeat this back and forth movement and stay looking at the image for much longer.

Cover up the foreground elements of this image and look at it. Now uncover the foreground elements. Does it make a huge difference to you? Follow your eyes' movement with the foreground covered and uncovered. Do you notice what I am talking about?

          The foreground elements add color and lost of interest. It pulls your eyes back and the looking process starts over. This helps to arrest the viewer's attention for longer.

          The foreground element also helps to create a lot of depth for this image. The plant and the brightly lit rock cliff create a lead-in line which just transports your eyes into the image.

          In this case, the strong foreground is not just based on interest but brightness and color. Find some colorful flowers, a little bush, or where the sun lights up. Compose your image with these elements in the foreground and your images will improve.