Illustrator - drawing shoes using layers

Working with Illustrator, I created outlines of shoes by using an image of a shoe and adding a second layer, making the first layer a 'template' and locking it to stop the image getting drawn on, and the second layer called 'drawing'. Using the pen tool i click and dragged and adjusted the lines to create curves to make a perfect outline of my shoe. I could then fill in the outline of the shoe with a colour or pattern of my choice.