If you have a backyard where your dog can eliminate wherever he likes, your grass might look a little worse-for-wear. To prevent those dead spots in the lawn, try setting up a designated potty area in a section of your yard.
Use some cheap fencing to partially enclose an area you won't mind using for this purpose, and lay down some river rocks or cedar mulch. (Do NOT use cocoa mulch!)
You'll need to train your dog to use this specific area, so begin by leading him there on leash and encourage him to "go potty" (or whatever phrase you might use for such things). Only let him leave the area after he "goes," and be sure to give lots of praise and treats when he does. Think of it like training a puppy: make a big, exciting deal about going in the right place, but don't punish him for going in the wrong place. (Positive reinforcement only, please!)
Eventually, with lots of consistency and encouragement, it should become a habit for him to use the potty area before exploring the rest of the yard. There may still be times when he forgets, but your grass will be considerably healthier! Plus, having all the land mines in one place makes it easier for you to clean up as well!
Bonus tip: after setting up a potty area in my own yard last year, I replanted the dead spots with clover, which is more tolerant to the nitrogen in dog urine than grass.