@Ceru I'm still using the solid cubes, they're good for practicing and colours can be quite nice. Yes, I used several layers of different colours; for instance in the mask of Ghilan'nain, the first two layers are of the same colour (lavender-y) and the third a different one (dark blue) Because watercolours let the bottom layers show, what you see is the combination of all layers.
Many times I wish there was a Ctrl+Z on traditional media, the "Oh sh*t!!" moments are much worse
When I see video tutorials that are often made with digital, I think "I wish I could do that!" But I love the organic feeling of traditional media, when I rub the graphite with my finger to soften the edge of a shadow or put a little more water on the pencil. I love digital drawing as well and I want to try it in the future, but for now it's one step at a time 
Where do you see other artists working? Picarto? I find it very useful to see other people work, as you say you can pick up tips and then apply them to your own style.
@Tesh I completely agree, watercolours require patience but the results are so beautiful. I love them combined with pencil, both coloured and grey
I think watercolours can be quite easily combined with other media, so there's a lot of room to play!
I began shading on the steampunk couple; if I had a digital eraser, I would make the lines softer to tone down a bit the cartoon look and make the shadows more realistic. Alas, I have to take it into account for the next drawing. You'll notice there's a certain point where I stopped because I'm afraid to work on it 