I actually like the first one, since she's peeking out and leaning over it makes sense to me that she's at an angle. However with the one of the iron fence, that in particular shows why it's necessary to practice a lot so you have your camera straight (to me that's a basic skill that needs to be learned).
I like the idea of framing the subject with leaves, branches, flowers etc. But if a leaf or flower is close to the camera (and depending on what aperture you use and what depth of field you have) then it can create big blurry out of focus blobs that seem distracting instead of adding to the composition.
I'd keep practicing, you seem to have a good eye; work on noticing your framing and how everything looks in your viewfinder (so you don't catch the edge of a shirt or jeans, try just above the waist or somewhat below but watch for shirttails and girls with long hair so nothing's getting chopped off in pictures).
I like the ideas you have, the woman in the gold sweater with gold leaves looks lovely together, and some of the fence and stone steps from the side work being at an angle (that's where you need to think about how those lines and shapes look in the composition). But I'd watch the backgrounds, you don't want half a car that's relatively close to the subject in the picture, think about where to have the subject sit/stand and where you'll stand and if that perspective works and how the background looks before you start taking pictures (if need be, move the person, move your feet - yourself).
Did Darrel already mention the book by John Szarkowski? The Photographer's Eye, not the one with the same name by some other guy. Or, if you don't have any art background, try googling 'elements of composition in art' (not photography) and that should bring up some sources of info. geared to students that cover line, shape, space, etc. and how those work together in a composition.
And go practice, practice, practice. You seem to be on the right track.