Looking good Naen!
By the way, are you using a mouse to draw those lines? You might consider getting your hands on a cheap drawing tablet, since that would allow you to taper your lines so you don't have to resort to changing the thickness halfway through a river. You can just gradually change the pressure of your pen as you go along, and your lines will automatically become thicker/thinner. Would work wonders on those mountains too.
I know purchasing a tablet for just one map sounds a bit silly, but know that there's options out there that don't break the bank: the cheapest one I could find (in a one-minute run) was just about 25$, although I'd personally recommend to go for something a little more than that. Check out
this page to get an idea of what's out there. If you decide to go for it and give it a spin, I'm sure you'll wonder why you ever hesitated getting it. I for one wouldn't even want to begin drawing a map with just a mouse!
Other than that though, I really like the layout of your map, AND your linework. Keep it up!