leash training a puller (Baby, Shih Tzu)

Baby pulls like a little tractor. Every walk in the soi became a fight and my arm was tired after 5 minutes. What finally worked for us is this: Stop walking the moment the leash gets tight. Do not pull back, just stand still and wait until she looks at me. Then we walk again. It takes forever at first, but after a few weeks she started checking on me before pulling. I also changed to a harness that clips on the chest, not the neck. It helped a lot because she could not choke herself. Treats in my left hand and I reward her when she is next to me. Keep the sessions short, around 5 minutes.