I only had a single image to work from which wasn't a bad photo but was of low resolution so not particularly sharp and difficult to extract much detail from when zooming in. When scaling up as in this case it helps to have as much detail as possible otherwise too much guesswork makes it difficult to make a representation of the character of the particular animal; the client requires a likeness of a much-loved pet rather than a generic image.
But I thought this still good enough to do a decent job, and set about the task by first of all drawing in as much detail as I could in pencil, then a light watercolour wash to set a gauge for the tone of the light and dark areas.
At this stage I wasn't particularly happy with the way it was working out and was quite prepared to start again, but persisted by inking in over the pencil marks and graded the shading using dots of varying sizes and intensities.
Stronger watercolour washes then followed which masked a lot of the inkwork and I'd somehow managed to pull it around, so finished off with Coloursoft pencils for highlights, a bit of texture and blending.
After sending the client an image for approval I had to make a few slight adjustments to make him just right, (eye colour is especially difficult to judge in photos) and here he is :
watercolour, ink and coloursoft pencils.