Dry fire practice will help. By removing the recoil you can see if the sights are moving or not. Move your finger around on the trigger and see what works best while focusing on the sights or red dot. Once the sights/red dot no longer move as you press the trigger then it's time to take it to the range. As scattershot mentioned, I too had to move my finger in all the way to the first joint on the trigger. Next you will need to "press" the trigger straight back. Any side to side movement of your finger can move the gun around. Once you get this figured out your accuracy should improve.

My Shield was the first striker fired gun I had ever owned and it took me a couple thousand dry fires to get that sorted out and burned into muscle memory.