Lookin' pretty good - can't go to wrong with Ascension's tutorials and I like the fact that you are modifying/adjusting things to your own 'style'.

Though I do agree with Alfar - I'd lighten up the stroke on the coastline.

As for the dark cloudiness, you could try to add a new layer (fill w/white and set to overlay) above that layer than merge them. Not sure how that will work, but might be worth a try.