I have found that vertical can make for an interesting design especially against or with non-vertical elements, such as the colourful foliage in these two photos.
Frames are useful when you can find them.
Foreground elements can improve a composition a lot. If I had just shot this photo from eye-level concentrating on the background trees, I don't think it would have been as interesting. (And we have verticals too.)
An example of just pointing the camera down to emphasize the foreground leaves. Also there is a leading line which leads the viewer through the frame, or at least I hope it does.
I used the curve of the river to try to draw eyes through the photo. I could have shot just across the river and did that too, but I think this is more interesting.
That's it for now. I don't necessarily consider any of the above to be praise-worthy. I was just trying to illustrate some ideas without using photos that I have presented previously and that I may have liked better. Or not.