Daily practice is the key, as it is with anything. You dont need anything special to do it, just the gun you have, and thats what you should be practicing with anyway. The nice thing with a DA gun is, you dont have to do anything between "shots" to reset the trigger. Just pull away.
The main thing with DA/DAO shooting is to focus on holding your sight alignment as you stroke the trigger. Dont worry about the trigger, just focus on the sights. Its going to feel strange at first, but once your muscle tone starts to pick up, youre going to find in a short while, it feels very natural, and your shooting will improve, and greatly too.
The transition from DA to SA isnt a big deal, and again, if youre focused on the sights and target, and not worrying on the trigger, youre not even going to notice it.
Youre going to find that that daily DAO practice will make you a better shooter overall too, and not just with your handguns. All your shooting will benefit.
It seems these days, so many are convinced that you need some sort of tuned, aftermarket trigger to shoot well with, and between the internet and the gun writers, etc, its constantly stressed that you do, which I believe it total BS.
In reality, I think its more of the state of things these days, with everything being less physical and more techie. Just look at the kids (and the adults too for that matter) these days compared to 50 years ago, and I think youll understand better.
The more in shape you are, the better youll shoot. That set of muscles that run that trigger finger, arent the only set of muscles that have been atrophying due to laziness.