Dry fire can be very helpful in determining exact finger placement on the trigger.
Find a safe place to dry fire, remove ALL ammo and loaded magazines from the room/area. Double-check the weapon to make absolutely sure it is COMPLETELY unloaded; no ammo in chamber, and no magazine in place (unless an empty magazine is needed to activate a magazine disconnect function to enable dry firing).
Watch the sight alignment, especially the reaction of the front sight, when you squeeze the trigger and dry-fire the weapon. If the sight moves in any direction when the striker releases, slow down the pressure on the trigger. If that does not correct the problem, then begin placing your finger on the trigger in a different manner. Try at least ten dry-fire shots for each placement. As said above, some designs work best with a little bit more finger on the trigger than the normal amount. You said you were using the tip of the finger; try the center of the first pad of your finger. If that still doesn't stop the front sight from moving/jerking when you gently squeeze the trigger, then try moving the finger so the first joint in on the trigger, then try at least ten shots. One or more of these adjustments should allow you to get to a solid squeeze-to-release without any sight movement when you hear the "click."
Then, try it during your next trip to the range, using live ammo. Take your time, don't rush the squeeze, and see if the shot placement AND grouping of the shots improves. If it does, make sure you use this grip and finger placement consistently for the next few range trips, to get it ingrained as a good habit. A little bit of dry firing each day (40-50 shots) will help solidify the proper habits.
"Placement is power" -- seen in an article by Stephen A. Camp
(RIP, Mr. Camp; you will be remembered, and missed)