Start by getting the overall shape of the body, neck and head, the head being the smallest part can be used as a measure for the rest.
Here I would like to mention a very useful tool for getting proportions right, it’s called the 'Proportion Measure' and is included within the full eBook.
Please make sure you sketch lightly as you will want to remove any unwanted lines later.
Next start to sketch in the legs and as mentioned above use the head as a measure, once you are satisfied that all these are in proportion you can start defining the animals shape.
Next you can start on the detail but before you do so you can erase any unwanted lines, otherwise it will be difficult once all the details are in place.
Now you can render in some shading, this will give it a more three dimensional appearance also any markings.
