Congratulation! It's a very difficult illustration to deal with it! I especially like the colours! And using watercolour into an environment scene like should have been very time-consuming! I've got nothing to say about the colour, I like it very much and the drawing is nice too. If can I give you any suggestion to improve I would say to learn to be more accurate with the perspective, especially in the curved lines (I struggle with it myself) and a tip that was given to me by a comic artist that improved a lot my drawing was avoiding central perspective and symmetry in composition; it feel artificial and a bit "boring". Another thing you could do to improved your composition is using more overlaps, they make the pace deeper (see how nice is that table that covers the feet of the age to the left? It makes really clear that the wizard is behind the table and that create deep and make the scene more interesting, use this technique more!). If You are a little confuse, don't worry they're are some advanced tips that I've fully understood quite recently so there's not need to rush! But I hope that they could help you to improve faster than me! ^_^" You're very talented, keep going! :D