One of the most fundamental challenges of landscape photography (and many other genres) is taking a three-dimensional scene and translating it to two dimensions in a way that still conveys the depth of the environment. Mastering this will significantly improve your landscape images. This excellent video tutorial will show you the ins and outs of controlling depth and perspective in landscape photos.
Coming to you from Photo Tom, this fantastic video tutorial will show you how to use depth and perspective to improve your landscape photos. One of the most common mistakes new landscape photographers make is not considering depth. Since landscape work often employs very wide focal lengths, which tend to push the background away and flatten it, if you do not include a foreground element of some sort, the frame can end up looking very flat, almost like wallpaper. The inclusion of even a small foreground element, such as a well-placed rock, can restore that sense of depth and give the viewer a nice place to enter the image and move through it to the background. Check out the video above for the full rundown.
And if you really want to dive into landscape photography, check out "Photographing The World 1: Landscape Photography and Post-Processing with Elia Locardi."