As with many models done in box modeling, let's start with a cube. The model is symmetrical so let's make use of it. Add a loop running vertically at the middle and delete the vertices on the left, leaving you with only half of the cube. Now add a mirror modifier.
Initial box
Now add a loop running horizontally and fashion out the torso.
Forming the torso
Add a vertical loop on the torso so that we will have more geometry to work on.
Adding more geometry
Extrude the head and the legs. Add loops around the head and the bottom of the legs and extrude out the head and feet.
Extrude head and legs
The model at another view
Now add a loop around the torso and extrude out the arms. This is all for blocking
Extruding out the arms
From another view
Detailing and Finishing
Add a loop that goes through the torso and the arms and another at the sides. This geometry will enable us to round and shape the figure.
Adding more geometry and rounding the figure
Extrude out to form a rough hand. Add an extra loop around the hand and extrude out the thumb.
Extruding the hand and thumb
Add more loops around the arm, thumb and hand. Work out this additional geometry to shape the parts.
Shaping the hand
Add this loop to add more geometry on the legs and to the torso.
Adding geometry
And then shape.
Shaping
Add more loops on the leg and shape out the form.
Forming the legs
Now time to shape the foot add more geometry and shape out the foot.
Initial form of the foot
Final form of the foot
Now take a look at your model. Adjust the form until satisfied. Work finished.