There are many ways to start drawing an animal, but one way is starting w/ basic shapes you can see in the animals body, for example the horse.  The back end of a horse, jaw, muzzle & joints are circular.  From his shoulders & chest down to the start of his legs are a pear shape.  By starting w/ these shapes, put in the right location, & then joining them you can draw a horse.  Have the body a little shorter & legs longer would be the body of a colt.  Let’s look @ a normal horse standing.

By doing it like this you can get your horse shape.  You can have them lying down, cantering, trotting, or whatever movement you want them doing. The more you use this method, the easier it gets & you can eventually omit the basic circles because you’ll be able to visualize where they’d go.  

You can use this technique for drawing any type of animal, just look @ shapes forming the animal.  Rough-in using a light pencil so you can erase what lines are not wanted before completing your drawing.