Northeastern countryside! What a beautiful setting.
I’m glad that you don’t have distracting elements in the foreground. It’s not always easy to find vast, clear overlooks that it appears you are standing on here.
You have plenty of leeway in your shutterspeed to compensate for a much lower ISO. That’s what I’d change first. Once you’re down to 100 or 200 ISO, I’d look at my shutterspeed again and if I still have room to make it slower without causing any camera shake blur, than I’d move up on my aperture.
In terms of composition, I’ve been in your shoes. One evening in New Hampshire I was standing on a hill I would guess was very similar to the one you were shooting from. There was nothing to use in the foreground (at least that I could find in time before the color faded) so I just zoomed in on the element that was the most interesting in on the horizon. The attached image was the best I could manage.
In my image, if I had zoomed in further to completely crop out the light part of the sky, I feel it would have proved too little contrast in the sky for the eye to pick up and enjoy. Zooming in even further to completely crop out the field in the foreground would also have rendered the foreground trees as a shapeless mass. So in my opinion, incorporating a little of both helped add interest to the shot. (See second attached image that is zoomed in a litter further than the other.)
Applying this train of thought to your image, compositionally speaking I would have zoomed in further on the “hump” that is close to the center of the frame right now, positioned it to the left of the frame (on a third?) but still keeping a sliver of blue sky at the top and some green field at the bottom. Zooming in in general is needed, but zooming in specifically in this way I think would make for a more compelling shot.
