The key here is not to induce any movement in the muzzle while you engage the trigger or while the projectile is traversing the barrel.
First, let's talk placement. Wherever your finger naturally lands on the trigger is fine as long as you can actuate the trigger straight to the rear. Generally speaking, you want the middle of the first pad as low on the trigger as possible. If you have too little trigger finger, you tend to push the rifle to the left. Too much trigger finger, you tend to pull the rifle to the right (assumes right handed shooter).
Some heavy triggers will require you to bury your trigger finger all the way to the first knuckle. Again, as long as you don't push or pull the rifle while you engage the trigger, you will be fine.
Some people teach that the trigger finger should be C shaped - I disagree. I like my the first and second joint of my trigger finger to remain straight. All of the pressure to engage the trigger is done from the second knuckle.
Ensure that you do not 'milk' the grip as you engage the trigger. When you actuate the trigger only the trigger finger itself should be moving.
Engaging the trigger is only half of it - you need to follow through. It takes 1/10th of a second for the hammer to fall, ignite the primer, ignite the powder, build up pressure and actually send the projectile down the barrel. Do not induce any movement in the barrel while this is taking place.
Hold the trigger back. Ride the recoil. Smacking the trigger or bouncing the trigger is not fundamental shooting.
The most efficient use of the trigger is to hold the trigger to the rear. Once the rifle has recovered from the recoil, relax the trigger finger just until you hear and feel the sear re-engage. Your finger should not come off the trigger until you have made a conscious decision that you are done shooting.
Some people say let the shot surprise you - I disagree. Your trigger is a mechanical device. Learn your trigger. Know how much slack you can take up right away. Know where the pressure wall is. Know when the shot is actually going to break. Concentrate; really think about it. That doesn't mean anticipate the recoil or throw your shoulder into the shot (buck). Know exactly when the shot is going to break so you can ensure your sights are on target at that moment.
Want to improve your ability to control the trigger? Practice! Train your trigger finger.
Unload your firearm. Sit with the rifle across your lap. Close the bolt and disengage the safety. Put your trigger finger low on the trigger in the middle of that first pad. Exhale to the bottom of your breath. Pause your breathing and SQUEEEEEEEEZE the trigger.
Hold the trigger to the rear - do not let go. Use your support hand to work the bolt. Slowly release pressure on the trigger until you hear and feel the reset point. Repeat the process 20x.
A more advanced regimen - pick up the pace. Do the trigger reset while you are breathing in. Make sure you are at the bottom of the breath and you have paused your breathing before you actuate the trigger again.
Use a laser bore sight (as suggested in the NPoA section) and ensure that the laser doesn't move while you actuate the trigger.
Put a coin on your front sight or the top of your barrel. When you can drop the hammer 10x in a row without the coin falling off you understand trigger control.
2 min of practice 3-4 times per week will dramatically improve your ability to control the trigger