Several Questions

Ok, so this is what I want to do and am having problems finding where to do it.

1)adding next and previous post links directly beneath the “post comment” button and above the hr (since beneath it becomes the footer).
2) centering the footer’s nav bar (it’s currently left align)
3) adding padding between the featured image and the beginning of the article
4) lastly, I would like to change the theme to blue and green because my website is about travel (but subtle colors). so which would be the nicest iterations of blue and green to do this do you think?

THANKS!