Your first block-in shapes won’t always be circles and ovals. Animals with angular features are often blocked in with straight lines, but the principle is the same; establish the general shape of your subject first, and build on that foundation. You’ll be amazed at how easy it is to draw even the most complicated subject if you’ve made blocking in a habit.
Think of the dog’s head as a rectangular wedge as in step A, and then place the features with very simple lines in step B. Block in the top of the dog’s head in step C, and make a few strokes for the ear. To finish, refine the outline as needed, and use loose strokes to suggest the dog’s coat.
Draw your own pet—it’s good practice and a lot of fun!