I'm afraid I'm not very familiar with CC3 (which is probably the case with the majority of seasoned artists here), so I can't offer any insights on technique. Also, at this scale it isn't easy to make out much of the details, so I'm not sure what the colorful balloon like objects are in the eastern-most forest (a magical fairyland perhaps?). You also have an odd river in the southeast, just below the main bay, which ends in a desert (or something) and then begins again. Is there a story here? Does the river somehow flow underground and then reemerge?

Cheers,
-Arsheesh