As someone who has only used the offhand position for hunting. I've had a bit of practice in 62 years of hunting and hundreds of animals taken. I also have won many BP shoots. I absolutely love shooting off hand, and would never consider shooting any other way.
I can't add a lot to what has already been said, except one point about breathing. First off my position is pretty much like Daryl's. Even the pointed finger which I did naturally as a kid. It's almost like pointing where the bullet is going. I also agree it's impossible to hold steady, so I don't even try to. I make sort of a figure eight layed down sideways with the target right at the middle of the eight. I pull the trigger that section of the eight. I did say pull. Maybe a squeeze pull, but definitely a pull. A slow squeeze is for much steadier positions that can be held steady. Of course the squeeze/pull must be made so it doesn't disturb the sight alignment. You're trying to time the pull of the trigger as the front sight passes the center of the figure eight. You have a nano second to get that done. A slow squeeze won't work for repeatable accuracy.
You also have to time one more thing. Breathing! I didn't read anybody doing it my way, so i'll mention it. Taking breaths, letting half of it out and holding never worked for me. It created tension for me. If you take notice of your breathing you see that you pause between breathing out and in. Thaqt's when you want to shoot. At the natural pause. Breath out....pause...breath in. The pause it natural and not forced, or even thought about. You don't want to think about it, except at first. Then it will be forgot in time and you'll shoot at that pause without thinking.
The last tip and the maybe the most important. Practice practice practice. It takes a lot of it to be a good offhand shooter, but I find it rewarding. It's also the fastest way to shoot while hunting. I'm a still hunter and most of my shots are taken fast. I don't have time to get into any other position. This forced me to become a good offhand shooter, and i'm glad it did.