From the Painting Guide: Traditionally in watercolours one would work from light to dark, because it's so difficult to remove paint successfully from a watercolour. But working from dark to light can also be successful. As with so many things, it's a question of trying both and deciding which you prefer.

I don't know how you approached it, but in this scene what I would've done is to paint the sunset and clouds first; let it dry; and then added the dark storm clouds and water. Painting the sunset colours all the way to the foreground and then letting it show through the dark water, is the easiest way to get this "reflected" in the water. You could even try masking out some areas with masking fluid so you don't have to paint around them.

Water is a tough one to capture. To me there's not enough of the sunset colours in the water in the top version -- it's created a very dark area that by comparison to the sky doesn't hold your eye. Even if the colours weren't there in reality, I'd use artistic license to add them. As it is, I'd be tempted to crop off the bottom third of the painting, just below the bit of land on the right-hand side, so that the sky dominates the picture.

If you like working fast, I'd suggest experimenting with painting wet on wet ie wet the area where the water is, then before it's dry dab in a brush loaded with some strong colour. It's a technique that can be hard to control, but can give great results. Using a cloth or bit of paper towel to lift out areas works well too with wet on wet.

It could just be the way you've scanned/photographed the painting, but the horizon line looks skew to me, causing the water to look as if it's flowing off the bottom left-hand edge of the picture.