Adobe Illustrator Practice (Dog)

During the last lesson of 'Adobe Illustrator for Beginners', the trainer wants us to practice drawing our a character, which can help us in our final project. He teaches us how to draw a dog for this practice session. We first get the picture of the dog from http://www.ohnitsch.net/wordpress/wp-content/uploads/2010/12/101024_dog_sketch.jpg.

Personally, I have difficulty sketching the outline of this dog using the pen tool as there are visible lines which are not meant to be sketched out. I did a bit of adjustment after the trainer give comments on my sketching. After adding the gradients, I finally get the picture of my dog.