A couple of safety things that I always have in my boat specifically for towing and backup of my water toys:
-self centering tow harness
- 6 rider capacity tow rope
As others have mentioned, tie off to the bow eye, not the cleats in the front. 2 reasons for this, bow lift and strength of anchor point. use the tow harness and attach to both eyes on your transom. It splits the force and is easier on your boat. The weakest point in the setup is the rope of the harness. The forces are pulled in such a way that if it does snap, the rope is going sideways and is not long enough to injure someone in my boat.
Since I am towing, I consider myself in charge, the captain of both vessels. They listen to me or they don't get towed. Period. If the disabled boat is capable of doing so, their trim goes all the way up. If not, their steering wheel is centered and tied off to minimize movement. My least favorite thing to do is fight someone trying to "help" by steering their boat. As others have mentioned, everyone in my boat or the stern of theirs if I don't have enough room.
One other strict rule I have is the driver of the disabled boat is not allowed any more alcohol. They need to be in the right frame of mind to retrieve their disabled boat safely. This has only been an issue one time with all of the boats that I have towed, he cracked a beer while I was attaching my line to his boat, I told him to get rid of it or I would not tow him. He took that as a sign to chug it. I helped him flag someone down to help him and took off. If he isn't concerned about me, my rules, and safety, I am not interested in towing him. I would never leave him helpless and floating in the water alone, but I am not going to tow him.