Congrats!
The answer is dryfire!
Watch the sight closely as you dryfire. the front sight shouldn't move when the "shot" breaks. experiment. See what grip adjustments, finger placement adjustments, etc works best. Once you get fairly good at this, you can progress to balancing a dime on the front sight and working to break the "shot" without disturbing the dime.
focusing on the front sight is key!
then, when you get on the range, you might still have some adjustments to make, but they will be minor. And you will have trained yourself to watch the front sight through the shot breaking, which can help avoid flinch issues.
I for one do not think there is a single answer to these questions. The shooter, their grip, and the gun all makes too much of a difference to universally say "oh you need more finger on the trigger." experiment and observe.
You can always hit the slide release with your weak hand thumb. this is how I run 1911s.
-rvb
"Focusing on the front sight is key".
Bingo, we have a winner...