You can go to address bar by ⌘+l / Ctrl+l, but how can I go back to, or focus, the browsing area again?
[EDIT:] Does simply pressing Tab a few times work for you? [/EDIT]
There doesn't seem to be such a shortcut. What you can do is press CTRL+F, search for a word close to where you are on the page and then Esc.
Of course this is not really convenient, so you could also do what this other answer suggests and type
I hope this helps. Sadly, AutoHotkey is only available for windows but there might be a similar tool for Mac.
Another option I just found out about: On windows, I can press Alt followed by Tab. This might work on mac as well.
There's no good way to do it, but if you're focusing the address bar to copy the URL, you could install something like Vimium, it ads
yy hotkey that saves the URL to the clipboard.
Pressing Tab should be doing what you want. This works even when the page has no focus-able elements. Tab will cycle though all the focus-able page elements and return to the address bar/location field, and whatever other browser UI controls can receive focus, in a loop, in that order.
More complicated example with other browser UI present: with the Inspector open, then setting focus to the address bar/location field pressing Cmd+L/Crtl+L, pressing Tab proceeds from the address bar/location field, to the next browser UI controls, which is the Inspector (and through all it's focus-able controls), and then to the page.