Yeah, I agree with Diamond on the grasslands, and otherwise it looks okay. One suggestion, or two, for creating the watercolor effect: A background with a bit of texture/graininess (and a brush with same), along with setting the paint layer style to either multiply or color burn (with the opacity turned down) goes quite a distance to improving the look and feel of digital watercolor washes. Your lake isn't too shabby, actually. Depending on your software, I think if you could capture some of that round bit at the top of the lake and turn it into a greyscale brush... that'd be useful for this application.