Welcome Funk... so happy to have you here. In addition to all of the excellent comments above, let me throw a few things out there that you can think about.
Do you understand the difference between 'sight alignment' and 'sight picture' ? While focusing on the front sight (the rear sight and the target will both appear fuzzy) try to maintain proper sight alignment. Proper sight alignment for your Glock 17 with 3-dot sights would be having all three dots collinear with the front dot equidistant between the two rear dots. While maintaining focus on the front sight, superimpose the aligned sights over the target.
Your pistol is probably setup to shoot 'point of aim equals point of impact' at a specific distance - maybe 50 feet or 25 yards (this distance depends on manufacturer preference). This means that the bullet will impact the target on the spot covered by the front dot. The exact point of impact, of course, will depend on distance and the type of ammo you're using. When first learning to shoot, you can ignore these differences and just concentrate on keeping "the dot on the spot" - and this is the proper 'sight picture'.
So... you're keeping the
front sight (1) in sharp focus, (2) lined up properly with the fuzzy rear sights, and (3) superimposed over the spot you want to hit on the fuzzy target. Now the trick is to maintain this sight alignment and sight picture as you slowly press the trigger straight back using your trigger finger's first pad. Don't slap, jerk, push, or pull the trigger - just a nice slow increasing pressure until the shot breaks. A little wiggling of the front sight is normal but with practice you learn to control the wiggle.
Now there's shot follow through. After the shot breaks, resist the urge to lower the gun to look at the target. Managing your gun's recoil involves re-establishing proper sight alignment and sight picture as quickly and smoothly as possible. As a new shooter, you also want to learn what the trigger feels like when it 'resets'. When the shot breaks, the trigger will be all the way to the rear. As you are re-establishing sight alignment and sight picture, slowly release the trigger while maintaining slight pressure on the trigger. You will feel, and possibly hear, a little "bump" - that's a bad way to describe it but what you're experiencing is the reset of the trigger. If you are going to fire another shot then do not release the trigger any further than its reset point.
So... you've fired a shot, re-established sight alignment and sight picture, and reset the trigger. You're now ready to do it all again.
You may have heard or read about 'dry fire' practice. This is practicing shooting fundamentals with an
UNLOADED gun. The emphasis here is on
UNLOADED.

With your unloaded pistol's muzzle pointed in a safe direction, you can practice sight alignment, sight picture, trigger press, and trigger reset anywhere you want for as long as you want. Dry fire is a good way to perfect these fundamentals. You can even make this practice a little more challenging by balancing a small coin on the front sight as you press the trigger - if the coin stays in place then you've executed an acceptably smooth trigger press.
Other components of breaking a good, clean shot are grip and stance. I'll let somebody else explain those.
Hope this helps.
