Whilst I do not have a how to guide, here are some suggestions.
Real dogs have a varied coat colour but tend to be a mix of black/dark brown on their backs running down to a lighter brown on their stomach.
So I would suggest painting the whole figure with acrylics the light brown colour that the stomach will be, then picking patches such as the back, head, legs in a darker colour, and also brushing in the direction of the fur.
Once this is done, oil washes of black, brown and tan for the stomach will bring out the detail, help pick out the fur and blend the colours together.
Once this is done you could pick out details like the nose (semi gloss black, since dog noses are normally wet) collar, and given that its a dog ...Mud!
Looking at photos of real dogs would also help match colours and work out what areas are which colour.
HTH
Anirudh