Making a rope harness for a dog takes only a few minutes. The type of rope used will vary by the size of the dog and requirements for the harness. For example, a huge St. Bernard will require a much thicker rope than a teacup Yorkie. Whatever the thickness of rope, it should be soft and sooth -- a fibrous rope can irritate the pooch's skin. Less than 5 feet of rope will be needed.
Measure the body portion of the harness. Most harnesses include two circles: around the dog's neck and torso. Measure the torso portion of the harness. Wrap a length of rope around the dog's torso, creating a circle, and see how easy it is to slip on and off the dog. The harness should be slightly difficult to remove and put on, so that it won't slip off the dog. Cut the rope at the appropriate length and tie it in a double overhand knot.
Wrap another length of rope around the dog's neck. Again, the rope should be snug but definitely not constrict the dog. The collar portion should be able to slip on and off without causing the dog discomfort. Cut the rope at the appropriate length and tie it in a double overhand knot.
Put the two circular lengths of rope on the dog -- one on the torso and one on the neck. Measure the distance between the two with a length of rope. Tie one end of the rope to the torso circle and the other to the collar circle, using a double overhand knot. The length should have a bit of slack to allow the dog free movement. The slack length will be determined by the size of dog. The dog should be able to sniff the ground easily without choking.
Clip a leash to the length of rope running along the dog's back that connects the two circles.