Lead The Eye
An object in the foreground of your landscape can act as a stepping stone to lead the eye onto the next interesting item in the image.
Lines are a more obvious way to lead the eye into and through the image and they can help emphasis points of interest as well as help give the image more depth.
Give Depth And Dimension
Having an object in the foreground can help balance the shot, give it a sense of depth and stop it appearing flat. Using a wide angle lens will further exaggerate the perspective of your shot.
Move The Horizon Up
If you want to emphasis what's at the front of your shot move the horizon up from the centre. That way you'll have less sky and more of your foreground in shot.
Depth Of Field
As you're featuring detail in the foreground as well as the background you want a shot that has front to back sharpness so make sure you're using a small aperture. This will increase your exposure times as less light will be able to reach the sensor so make sure you have your tripod
with you to stop shake spoiling your shot.
If you want to give your foreground more prominence, such as when you're shooting a field full of flowers, use a small aperture and a slower shutter speed to capture the entire field as it stretches from front to back.