Move a little closer. Snap that first picture from where you are and take in the whole scene. Then move a little closer, closer, closer still; now your subject fills the frame and you have more detail.
Keep the horizon level.
Keep it clear. Pay attention to the background and keep it clear of clutter so that the focus in on your subject.
Use your tripod more. Just remember to turn of the IS [VR for Nikon users] on your lens when you do.
Move. Move around your subject and shoot from different angles.
Keeping the sun behind you or at least to the side makes for better landscapes.
Take time. Think before you shoot and visualize what you want your image to be…
but at the same time… practice, practice, practice, practice. It is digital you can always delete those less than perfect shots.
Shoot in RAW. It captures so much more information that a quick edit to the RAW file can save you hours in Photoshop.