Because we can't control the light or conditions in landscape photography, it is quite important to plan ahead to ensure that the time of day and weather will be right for the photos you want to create. However, as important as that is, it is also crucial that you be willing to stay flexible if an unexpected opportunity arises or the weather is not cooperating. This great video discusses why being overly rigid can be detrimental to your work.
Coming to you from Steve O'Nions, this excellent video talks about the importance of not being overly rigid in landscape photography. No doubt, it can be frustrating when you put a lot of effort into planning a landscape image and the conditions do not pan out, but trying to force the photo into existence can just lead to more frustration and images that don't work. However, you can create worthwhile images in any circumstances, so long as you make photos that the conditions are conducive to rather than fighting them. Check out the video above for the full rundown from O'Nions.
And if you really want to dive into landscape photography, check out "Photographing The World 1: Landscape Photography and Post-Processing with Elia Locardi."