Sadly, the majority don't do it right

Many other force-free trainers also embraced the new design as a huge improvement over head halters, which were clearly aversive to many dogs. In contrast, most dogs seem to accept the front-clip harness instantly, with only a very small population who seem to find the harness aversive. In my experience, most dogs who object to the harness are sensitive to touch and/or handling, and it’s the process of putting the harness on, rather than wearing the harness, that they object to.

Petmate representative demonstrates putting on and sizing an h-harness for a dog.

Now there's a harness that I use quite a bit for large dogs who pull and large puppies who pull and even small puppies that pull. Sometimes you want to be sure that you're putting pressure on a dog's throat when they're too young, because their spine and their trachea are developing, and using a collar when pulling them around can really do some damage to their throats. So a harness like this is great.

How to Put on a Step In Dog Harness - Kurgo

Putting on dog harnesses is fairly easy and usually they are put on by going over their head and snapping underneath, behind... I have your top rated Balance Harness and personally I think it is poor at best for a few reasons......1st of all its hard to adjust and once you have it adjusted to fit as they want it the neck collar piece rides too high on the neck, 2nd the attachment for back piece and the neck piece is a triangle piece of metal putting a point on the withers. So many buckles and adjustment parts I don't see how it could be comfortable on the poor dog. The only good things I see about it is that the chest strap is to be adjusted at least 2 inches behind the elbows and that it does not cross the shoulders.
You can get an much better custom made harness to your dogs exact size for $2 more plus another $5 if you want the front ring.

3 Ways to Put on a Dog Harness - wikiHow

CONS: Straps can easily twist when not on the dog, which can make putting the harness on difficult. Single stitching at non-connection points.

How To Put On A Dog Harness | The 'How-to' Dog Blog - dogIDs

Whether it is a Step-in-Harness or an H-Harness that you are using, this Rogz Roovie will assist you in the correct method of putting a harness on your dog.A dog harness is a good choice for dogs who pull while walking on a leash. Dog collars allow pressure on a dog's throat while a harness transfers the pressure to your dog's chest instead to relieve the choking hazard. Putting on a harness and correctly adjusting it, takes a small amount of time before you are off on your walk.Each style of harness has its own set of techniques to consider when putting it on your dog. Typically, the harness will either require your dog to step into it or you’ll have to slip it over your dog’s head and the have him step through the arm holes before you clip him in. With any style, it is important to get your dog used to how you put it on so that you both stay tangle-free. “I recommend teaching the dog to stand still,” Angell said. “You could teach them to stand and put one paw through the harness and then the other. If the dog is a little fidgety, give him a treat to eat while he gets all harnessed up.""This is the second chest plate harness from EZYDog that I've had. My first one was for my little mini daschund, and I loved it. Easy to put on, doesn't go around the neck and post a choking hazard as so many do. So when my first baby died and I finally got another, slightly larger dog, THIS was the harness I wanted. I was given others to try, but they all entailed putting them on over her head, and put pressure on her neck. My best friend has been through THREE car wrecks with this harness on her dog, and the dog survived them all, when otherwise he'd have been a missile. CAN'T PRAISE THIS ENOUGH!!!"