One Year for a skill, One Year to get Real

[Spiffy]

If you want, I would suggest something like this:

I want to learn environmets:
Environments have-
Perspective (possibly largest challenge for beginners of environments)
Composition (leading the eye through your environment)
Depth (foreground, middleground, background)
Mood
Color & Light (hint: James Gurney)
Atmosphere
Scale, and scale-objects (a figure, that does not contend with the environment if the environment is the focus, man made things, animals, etc. Things that we already as the viewer know the scale of)

Now, not all environments use every single one in an overtly obvious way, but all use them to some degree. Knowing this, I would study each subject independently, and then every so often apply all that you know to a new composition.

Some masters, or schools thereof:
Impressionists (the above subjects, simplified)
Hudson River School

and of course, post progress :D