A few days ago, I promised to write something about landscape composition, so here it goes.
The hardest thing to understand about landscape painting is tone. When painting outdoors, the first thing to understand is that the range of tones (from the lightest white to the lowest dark) is much wider than you can accomplish with artist paints. JF Carlson explains this well in his book (see reference below)---noting that the range of tones outdoors is many times what you can produce on your palette. The tendency is to paint in the high range of tones, since sunlight makes everything appear so radiant. You must avoid this tendency to be a successful landscape painter. My friend Mitchell Johnson once told me that when in doubt he would take off his white t-shirt and put it out in front of what he was painting. Try this, bring a white cloth with you if you are painting outside and put it out in front of you. In comparison, nearly everything (if not all) of what is out in the landscape will appear darker. So, tone it down.
To learn more about landscape composition and how to control your tones, I would recommend two books. The first is by JF Carlson and has been around for many years--but is worth buying. You can get it in paperback on Amazon: Carlson's Guide to Landscape Painting.
The second book I highly recommend is by Edgar Payne, Composition of Outdoor Painting. This book is harder to find, but has been reprinted lately-so you should be able to find a copy. I know there is one copy left at Franz Bader bookshop in Washington, so give them a call if you need it.
Anyway, that's it for today. Just some thoughts and recommendations. Hope they help. Keep painting, even if only for sixty minutes a day. Sxtyminuteartist