Watercolor Tutorial

I was testing my new camera when I had the idea of taking photos of a few steps of my current drawing ^^. And here it is!
This isn't a real tutorial because I'm not a professional artist, it's just to show how I proceed. So if you have any ideas about how I could progress, it would be very helpful .
And please excuse my English too, it isn't my native language (that's the first time I type such a long text in English o_o).

Completed drawing: [link]