Thanks, J.! I'm glad you like the water, that was pretty much my favorite thing about this too.
I think most of the credit really does go to the textures to be honest (I was using a couple from Shutterstock and one from the wonderful Coyotemax's Aged Paper pack). Here's a little crop to show you what it looked like without them:
SyrUnfinished Crop.jpg
What it basicly consists of:
The 'outer ring' around the coastline. That's a separate mask of it's own, placed under the main landmass' mask, and completed with a separate lineart layer (with a color overlay of a little brown hue in order to give it more of the 'burnt' look you see with the textures on it). The elements being separate in order to gain more control over them, as I've always found the look to be a little artificial when you just use an Outer Glow or something like that on the main landmass mask.
Underneath that, you have the wavelines, and I really took the easy way out with them. I worked around the coasts with a brush like this:
wavies.jpg
After that I just made a selection a little bit outside of the 'outer ring' and Feathered the hell out of it, and used that as a mask. It doesn't look that great now, but the texture helped to edges to burn in quite nicely.
The rhumb lines added to that (white base with a soft little white Outer Glow to give it a soft look) and that's pretty much all there is to it. The texture does the rest.