I'm working on a short tutorial for you all to help you practice your shading technique. (Follow the White Bunny style obviously) I think it should be done some time next week. I made a simple cloud design and for the shading you will need several shades of the same colour.
For this small project I belief that working with a dark, medium and light version of one colour is sufficient. From a distance the eye will 'blend' the shades anyway, but you can add more if you are feeling adventurous. As to the colour: you can pick grey or any colour you want your cloud to be. Make sure the colours are good for blending though. If you look at the DMC colour chart (you can view one here) you will see that most colours that are within a colour family (close to each other) will blend nicely. I found that if you pick colours that are too similar the effect in your shading will not be as good as with shades that are bit 'further apart' so keep that in mind when you choose your colours.
Now I thought it would be fun if I would host a small stitch a long when the tutorial is on the blog! It's a really small pattern so it's not a huge commitment. Who is with me???