Start of with a circle
Remember you're not etching in to stone so sketch lightly and don't worry if it doesn't look perfect at this stage

Draw a curved line along the bottom half of the circle and another going vertically.
These lines also help to work out which direction your character is facing, you could experiment with different directions

Draw a inward curve on the cheek that is turned away from you, starting from near the top of the head and stopping at the horizontal curve at the bottom.
Also add a small curve on the other cheek, around the bottom horizontal curve.

For the muzzle sketch a small circle below where the two lines meet, this will help you to figure out it's shape.
You can draw in more detail the lines that you will keep in the final image.
You could try different sized muzzles
      

The eyes start either side of the muzzle, I tend to work mostly with rounded rectangles, it depends what kind of expression you are trying to achieve.

Make the eyes a little more detailed, adding darker lines along the top, the pupils can be round or oval, try different ways of doing them.

This basic shape can be used to create different eyes
  

The ears are drawn either side of the top of the head, these are a tear drop shape, but it depends on what kind of animal you plan on drawing.

Basic ears can be drawn using tear drop shape

Other things you could add are some fur on the side of the cheeks and eye markings