check out http://thesartorialist.blogspot.com/
Obviously nothing like your shots, but i think he takes fantastic 'out of studio' images.
IMO, try not to get hung up on rules etc but just shoot and think about what would look like a great photograph. rather than it having to be taken with a certain aperture or is there evenly distributed land/sea/sky ratio.
Also be selective with your processing techniques, i see you've applied sepia to one of your landscape shots and I'm not sure it really contributes to the picture. It does work better on the one of the guy mountainbiking though, although that again could do wiht the levels played with.
Overall though, you've got some nice photos and just go out and take more!!!