There are several indicators. A domestic dog track tends to be wider or more spread out, while a coyote track tends to be narrower, both in terms of the actual print and the gait of the animal.
Also, the outer toes of the coyote are larger than the inner toes, and it is the opposite in a dog. You also tend to see the prominent centre nail marks in a coyote track as well.
In softer ground, it can sometimes be hard to tell, but you can mark a near perfect 'X' through the pads of a dog track. Not so with a coyote.