Watercolor is really hard, you have to plan everything out very carefully. My best advise is to go slow, use thin washes and build up your values a little at a time. I have failed at watercolor myself a few times, so this is how I do it whenever I do it.

Overall I really like it! I think the drawing and mood are excellent! What would need some work is the value and color. I think it would help to brush up on values first! Another thing is the actual manipulation of the material. But that comes with time so you're on your way! Great job, keep it up!