I've been reading 'Painting Your Favourite Animals in Pen, Ink & Watercolour' by Claudia Nice (see my page of favourite books). I decided to try her method of painting fur, using a sponge.
I didn't have a bunny handy so I painted a bear instead.
Step 1: sketch with pencil, pen, and a yellow ochre wash. (I put a spot of masking fluid on the eye for the highlight). Wait till it's dry (note: using a hairdryer is not cheating!)
Step 2: sponge on a darker watercolour (not too wet) on the side facing away from the light. Wait till it's dry. Then I added the dark colours for the eyes, mouth and nose, and started on the blocks.
Step 3: Add more shading and some lines for stitching. I used the sponge and a brush for this. Wait till it's dry. Do some more on the blocks.
Step 4: Finish the blocks and add some shadows to the ground.