The method I used to get half way decent at Double action was to rack one, decock, fire DA... decock, fire DA... and so on... Paper plates are good for these drills... Speed comes later, so take your time.
Then I progressed to rack one, decock, fire DA, fire SA, decock, fire DA, fire SA, and so on... to get the difference in DA and SA trigger pulls down.
Then I started moving right... using DA, SA, SA... Then left DA, SA, SA... Then back DA, SA, SA...
As I got better, I started to increase range...
Now if I am confronted, you guessed it, DA SA SA until the "threat" stops... 2-4" groups at 25 yards standing still, and 4-6" groups moving... Good enough to defend myself, my family and property.
I hope this helps you out.
Then I progressed to rack one, decock, fire DA, fire SA, decock, fire DA, fire SA, and so on... to get the difference in DA and SA trigger pulls down.
Then I started moving right... using DA, SA, SA... Then left DA, SA, SA... Then back DA, SA, SA...
As I got better, I started to increase range...
Now if I am confronted, you guessed it, DA SA SA until the "threat" stops... 2-4" groups at 25 yards standing still, and 4-6" groups moving... Good enough to defend myself, my family and property.
I hope this helps you out.