One very likely cause of shooting low and left is not following through. The sequence of shooting should be focus on the front sight, press the trigger, recoil occurs, reacquire the front sight, get the front sight back on the target, reset the trigger and finally decide whether to shoot again. Please notice that the above sequence does not mention looking at the target to see you hit or miss. If you try to look at the target after pressing the trigger, you will move the gun usually low and to the left. It may seem hard to believe but your hand is faster than the bullet moving down the barrel.
Just remember that all guns will hit what they are aimed at. It is your job to do the aiming and hold the aim point.
We recently had Jim Crews give a intermediate handgun class in NH. Jim is an absolute magician when it comes to fixing handgun accuracy problems. The overall improvement of the class accuracy (including the beginning shooters) was astounding.